Indy Chronicler

History of Roman’s Aqueducts

Water has always been one of the most important urban resources, and ancient Rome was famous for its wealth of public fountains, baths, artificial pools and reservoirs, arenas for staging naval battles (navmachia), irrigation canals, and other such facilities.

Within about 500 years, 11 main aqueducts with many branches were built in Rome for these needs. It has been estimated that the daily volume of water supplied by these aqueducts far exceeded the needs of today’s city. This abundance of water, which no other place in the world had, gave Rome the name regina aquarum, i.e., “queen of waters”.

Interestingly, the Romans did not name the aqueducts themselves, but the water they supplied, and so most of these structures were called aqua (Aqua Appia, Aqua Marcia, etc.) with the name of the ruler or official who sponsored the work or supervised its construction.

Since the founding of Rome, its inhabitants could use the water of the Tiber, which flowed along the western border of the city (today the river cuts the city into two halves), and the Anienus, which flowed into the Tiber 4 kilometers north of the first city walls.

During the imperial period (8th-6th centuries BC) and for some time during the Republic, the city’s population met its water needs by bringing water directly from these two rivers, as well as from small canals and a number of other sources such as wells and rainwater tanks. But as early as the 4th century BC, the growing size of the city, as well as the increase in its population (including immigrants, visiting traders and slaves), demanded much more water.

In 312 BC, the censor Appius Claudius built the first aqueduct. It carried water from a spring located 7 to 8 miles east of the city and had its own length of at least 11 miles. The construction of subsequent aqueducts occurred at a frequency of once every 60 years or so, although in 52, two of the lower ones were built almost simultaneously. The last aqueduct, the Aqua Alexandrina (in honor of Emperor Alexander Severus) was completed in 226. It also ran from the east, but its location in the city is still uncertain.

The length of the aqueducts was expressed in passus (paces), corresponding to 1.482 meters or 4 feet and 10.25 inches. A more approximate measurement was made in milia passus, i.e., Roman miles or thousands of paces (1.482 km or 0.92 miles).

The aqueducts were managed by the curator aquae (curator of water), a high-ranking officer responsible for everything related to the city’s water resources. Toward the end of the 1st century, one such officer, Sextus Julius Frontinius, wrote a very detailed essay entitled “De aquae ductu urbis Romae” (“On the Aqueducts of the City of Rome”), which is the main source of information on the hydraulic structures of ancient Rome.

The following is a list of ancient aqueducts according to chronological order. It also shows which parts of the city they served. The location of the sources is given in relation to the center of the city, i.e., the Capitoline Hill, and distances are given in Roman miles and kilometers.

Aqua Appia

Built by the censor Appius Claudius Caecus in 312 BC. The springs were located 7-8 miles (10.4-11.9 km) to the east. The total length was 11.2 miles (16.6 km). The main outlet was at Circus Maximus, with branches going to different parts of the city.

Anio Vetus

The new name is Old Anienus. It was built in 269 BC. The springs were located 29 miles (43 km) to the east. The total length was 43 miles (63.7 km). The main outlet was at the Porta Esquilina (Esquiline Gate).

Aqua Martia

Built by the praetor Quintus Marcius Rex in 144 BC. The springs were located 36 miles (53.4 km) to the east. The total length was 61.7 miles (91.4 km). The main outlet was located on the Quirinal Hill.

Aqua Tepula

“Warm water” – the name is derived from the temperature of the springs. It was built in 125 BC. The springs were located 10 miles (14.8 km) to the southeast. The total length was 20 miles (29.6 km). The main outlet was at the Porta Collina (Collin Gate).

Aqua Iulia

Built by Emperor Octavian Augustus (family name Julius) in 33 BC. The springs were located 12 miles (17.8 km) to the southeast. The total length was 15.4 miles (22.8 km). The main outlet was at Porta Viminalis (Viminalis Gate), with branches going to different parts of the city.

Aqua Virgo

“Water of the Virgo” – the name originated from a legend (see Ancient fountains). It was built in 19 BC. The springs were located 8 miles (11.9 km) to the east. The total length was 14.1 miles (20.9 km). The main outlet was on the Campus Martius (Field of Mars).

Aqua Alcietina

Built in 2 BC. The source is Lake Alsietina (now Lake Martignano) 14 miles (20.7 km) to the northwest. The total length is 22.2 miles (32.9 km). The main outlet was at Trans Tiberim.

Aqua Claudia

Built by the Emperor Claudius in 52. The springs were located 38 miles (56.3 km) to the east. The total length was 46.4 miles (68.8 km). The main outlet was at the Porta Prenestina (Prenestine Gate), with branches going to different parts of the city.

Anio Novus

Anio Novus. It was built around the year 52. The springs were located 38 miles (56.3 km) to the east. The total length was 58.7 miles (87 km). The main outlet was combined with the Aqua Claudia outlet.

Aqua Traiana

Built by Emperor Trajan in the year 109. The springs were located 13 miles (19.3 km) to the northwest. The total length was 38 miles (56.3 km). The main outlet was located on Janiculum Hill.

Aqua Alexandrina

It was built by the emperor Alexander Severus in 226. The springs were located 14 miles (20.7 km) to the east. The total length was 15 miles (22.2 km). The main outlet was at the Pantheon on the Champ de Mars.

The capacity of each aqueduct was expressed in quinariae. It is estimated that 1 quinariae equaled 0.48 liters per second. The most powerful of the 11 aqueducts, the Anio Novus, produced 4,738 quinariae of water, which equaled almost 196.5 million liters per day!

The earliest graphic depiction of the aqueducts appears in the Forma Urbis Romae, a very detailed plan of the city carved in stone at a scale of 1:240 and dating from the early 3rd century. Fragments of this plan have survived to the present day.

Several Renaissance and Baroque maps of Rome show three-dimensional representations of parts of the aqueducts still in existence by the 15th and 17th centuries.

Thanks to these sources and archaeological excavations, it was possible to trace the routes of most of the ancient Roman aqueducts, although due to the development of the city over time, very few of these magnificent structures remain.

Aqueduct Design

Aqueducts collected water from several natural springs located far from the city. The springs were chosen based on a number of factors – their location, the purity of the water, its taste, temperature, and sometimes its healing properties due to the mineral salts it contained.

The only source of energy to move the water towards the city was gravity, i.e., the aqueduct had a continuous incline from the source to the final outlet. To achieve this result, the viaducts supporting the water tunnel were designed so that each segment along its length was slightly lower than the previous one and slightly higher than the next.

For this reason, water was taken from springs in the mountainous areas above the city. Most of these were found to the east of Rome. The route along which the aqueduct ran was carefully planned to suit the terrain.

The Roman architects in charge of this work (libratores) were quite skilled in their craft. In addition to the conventional level, which we still know today, they used such devices as chorobates and dioptra. The former was a bench with strings hanging from the edges and a system of notches to measure the angle relative to the ground, as well as a notch in the middle (probably to check the direction of water flow).

The Dioptra was a level of a different kind – it stood on the ground and was finely adjusted by rotating and tilting its top with precision screws. It could be used to accurately determine the angle of inclination of the section of the aqueduct being viewed.

PICTURE

Before entering the aqueduct channel, the water passed through one or more pools called piscinae limariae, where the flow rate was slowed to allow mud (limus) and other solids to settle to the bottom. Similar basins were installed further down the course of most aqueducts to remove any additional impurities.

Outside of the urban area, most of the aqueduct construction took place underground. The walls of the tunnel were covered with a waterproof mortar mixture with tiny fragments of broken tiles and amphorae, called opus signitum, 5 to 10 centimeters thick. The average size of its sections was about 1 meter wide and 2 meters high, but could vary considerably depending on the anticipated water head in each section.

Vertical wells were arranged throughout the underground portion of the aqueduct, used as service passages to keep the tunnel in order. The water of Rome, especially from the springs to the east of the city, is very rich in calcium salts, and huge amounts of sediment had to be removed regularly to prevent the ducts from narrowing. Special outlets were also present along the length of the tunnel to prevent the walls from being damaged in the event of overflow.

On the outside of the underground part of the aqueduct, a large stone was placed every 240 feet (70 meters) to mark the tunnel underneath. A strip 10 feet (2.9 meters) wide above the tunnel had to be kept clear to avoid damage and breaches. All aqueducts were public property, owned by the government and operated for the benefit of the citizens. The photo shows one such stone found at Porta Maggiore near a place called ad Spem Veterem. The inscription on it begins with the words HAC RIVI AQ[VARUM] TRIVM EVNT… (These are the directions of the three waters…), signifying the three aqueducts reaching this place – the Aqua Martia, Tepula and Julia.

Damage to aqueducts or water pollution was severely punished, as was the illegal connection of pipes from private property to the public canal. Private branches existed, but they were only allowed to take excess water and had to pay for it.

Due to the natural features of the landscape, some sections of tunnels could run on the surface along trenches whose walls were blocked. These tunnels were covered with stone slabs to protect them from direct sunlight and dirt. The slabs could be flat, rounded (domed) or angled (roofed).

Usually these open parts of aqueducts were protected by a low wall with some kind of roof, and the safety distance increased to 15 feet (4.4 meters) on each side.

If the canal reached a steep slope or ravine, two solutions were used to cross it. The first was to build a bridge, or viaduct, over which the canal reached the other side at a slightly lower level and returned underground again. The second method was the “inverted siphon,” a method based on a simple physical principle.

Water would be collected in a cistern in front of the slope, from which it would be piped down to the bottom of the depression by gravity and then back up again by the pressure created on the first slope. A small viaduct was often built at the bottom of the basin to reduce the maximum height and minimize the required water pressure.

The siphon method was not often used because the pipes, which at that time were either made of clay and joined together by sockets at one end, or of lead and held together by rather crude soldering, did not hold up well to the pressure created on the slope. This resulted in considerable water loss and the need for frequent repairs.

Instead, architects usually chose to lengthen the aqueduct, sometimes quite significantly, following the natural features of the landscape to utilize a simple slope. This explains why the length of most aqueducts greatly exceeds the direct distance between their sources and urban outlets. For example, the Aquae Virgo aqueduct had springs 10.5 kilometers east of Rome, but its own length was 20.5 kilometers.

As you approached the city, where the landscape became flat, the water flowed through the famous arcades, which in some cases were as high as 30 meters. It was through such impressive structures that most aqueducts entered Rome. The higher the level of the water brought in, the more neighborhoods it could reach.

The base of the tall pillars was made of concrete (opus caementicium), i.e., a mixture of stones and mortar. It was then, for aesthetic purposes, faced in various ways. It could be hewn tuff (opus quadratum, used for most aqueducts until the early Empire), or small square blocks of tuff arranged diagonally and alternating with rows of brickwork (opus mixtum, used in the Aquae Traiana), or simply brickwork (opus latericium or opus testaceum, used in the Aquae Alexandrinae). The Aqua Martia aqueduct, for example, was lined with three different varieties of tufa, which had a voxo-artistic effect.

The upper part of the plain aqueduct had a lid-like cover with a series of doors, allowing the same repair and maintenance work as in the underground tunnels.

In addition, on this upper part, the level corresponding to the water channel was marked with bands, also made of tuff, but of a different color.

To make the fullest use of both the natural height and the height of the created bases, several aqueducts approached Rome practically along the same route. Therefore, two or even three canals could pass through the same sections of one aqueduct, but through separate tunnels at different levels according to the height each reached at that location.

The main outlets of the aqueducts were located at the highest points of the city. Most aqueducts entered Rome from the southeast at a place known as ad Spes Veterem (Old Hope), behind the ancient Temple of Hope that once stood there. The water then descended into the city from the Esquiline Hill and diverged into different neighborhoods.

In some cases, the more full-flowing aqueducts “helped” others to provide enough water for their respective neighborhoods. For example, the Aqua Claudia poured about 1/8 of its flow into the Aqua Iulia and Aqua Tepula.

Not all aqueducts entered Rome “overhead”; the very first of them, the Aqua Appia, passed almost entirely underground. Such were also the Aqua Alcietina and Aqua Traiana, which supplied water to the 8th district, the Transtiberine (Trastevere), from the top of the Janiculum Hill.

In such cases, lapides perterebrati, special tuff blocks with a clay or lead pipe inside, were used inside the city. There may not have been a pipe. In such cases, the surface of the inner channel was covered with a waterproof layer. In the course of archaeological excavations, many such blocks were discovered, which allowed us to identify several underground water pipes mentioned in literary sources.

The Aqua Alcietina, the first of the two western aqueducts, delivered water from the small lake Lacus Alcietinus (now Lago di Martignano) north of Rome. This water was not potable – Emperor Octavian Augustus used it to fill his arena for navmachia (mock naval battles) in Trastevere and to irrigate Caesar’s Gardens in the same area.

The main outlet of the aqueduct was in the form of a castellum (castle), with one or more chambers, similar to the piscinae limariae, where the flow of water was slowed down again and the last impurities were deposited.

Outside, the water poured out through a series of bowl-shaped nozzles. Most castelli looked like simple prisms, but some had the form of fountains decorated with statues, reliefs and mosaics (nymphaea).

They were guarded by guards against spoilage and contamination of the water.

These “castles” sometimes had their own branches of aqueducts, ending in smaller “castles” or going directly to public baths and fountains. The whole of ancient Rome was actually crisscrossed by a complex network of aqueducts.

Aqueducts Nowadays

For centuries, the remains of ancient aqueducts have been one of the favorite subjects for painters and engravers, despite the fact that the best preserved parts of them are far from the central parts of the city. Today, the sites are just as densely populated, but until the first half of the 20th century, this was a rural area, and the ruins did not pose any obstacle to vehicle traffic or occupy expensive land. The further one moves away from the standard tourist routes, the more one can see well-preserved remains, some of which still boast their pristine power.

Destroyed during the conquest of the city in the early 6th century, the aqueducts became useless, cumbersome structures that became mainly a source of available building material such as brick and stone. Subsequent wars and earthquakes destroyed what was already left. All this resulted in the fact that in the old city boundaries, i.e. in today’s central Rome, there are hardly any traces left of the aqueducts. However, some interesting fragments can be found on the southern and eastern outskirts of the city.

Aqueducts at the city gates and their central branches

Before becoming the main southeast gate in the Aurelian Wall (275), the Porta Prenestina (now Porta Maggiore) was the double arch of the local aqueduct. The same can be said of the eastern gate, the Porta Tiburtina.

In fact, where aqueducts crossed important roads, such as the aforementioned Via Prenestina and Via Tiburtina, arches were built with special decorations dedicated to the sponsors of the aqueduct’s construction (most often the emperor).

When the new city wall was built by Emperor Aurelian, these two arches were incorporated into its defensive structure. And despite being turned into gates, the arches continued to act as aqueducts, carrying water in their upper part: the Aqua Martia, Aqua Tepula and Aqua Iulia passed over the Porta Tiburtina, while the Aqua Claudia and Anio Novus passed over the Porta Prenestina.

The area immediately in front of the Porta Prenestina was called ad Spem Veterem. Five different streams (actually six, counting the underground Aquae Alexandrina canal, which has never been found) converged here. They provided 70% of Rome’s water supply. The drawing shows the directions of these aqueducts according to the archaeologist Rodolfo Lanziani (late 19th century), and the three-dimensional elements are adapted from Du Perac’s map of ancient Rome (1576). The parts redesigned by Pope Sixtus V for his Acqua Felice are also represented. What still exists is colored brown and what has been lost is in light gray.

Aqua Martia, Aqua Tepula and Aqua Iulia ran along the Aurelian wall towards Porta Tiburtina. Before reaching the gate, the Aqua Martia separated from itself an important branch called the Rivus Herculaneus, which probably served the nearby nymphaeum of the Licinius family, better known as the Temple of Minerva Medica.

The Rivus Herculaneus carried water to the Caelian Hill, in the southern half of Republican Rome, and then went underground and ran parallel to the Aqua Appia to the Aventine Hill (southwest). Nothing has survived of this branch except isolated sections of the underground canal.

At Porta Tiburtina the triple aqueduct diverged from the Aurelian wall towards the Quirinal Hill, i.e. to the north. Here another large branch, built towards the end of the 3rd century and called the Aqua Iovia, separated from the Aqua Martia. It carried water to the huge complex of Diocletian’s Thermae.

In 1587, this part of the Aqua Martia was rebuilt into a new aqueduct, the Aqua Felice. At the end of the 19th century, due to the construction of the Termini railway station, all sections of the viaduct from Porta Tiburtina towards the city were removed. Only its first 100 meters were left. They end in an arch glorifying Sixtus V, located at right angles to the wall of the railway station in Piazza Sixta V.

The Aqua Claudia and the even fuller Anio Novus had a common outlet near Porta Prenestina. The last ruins of their castellum disappeared at the end of the 19th century.

Arcus Neroniani, or Arcus Celimontani

Before reaching its main exit, the Acqua Claudia separated from itself a large branch that Emperor Nero had built for his Golden House. Hence the old name Arcus Neroniani, i.e. the Arcus Neroniani (Nero is the family name of the Claudian dynasty).

After the Golden House was destroyed, the branch was changed to point towards the Caelian and Aventine hills, and renamed Arcus Caelimontani, i.e. the arches of the Caelian Hill or Caelimontium, as the second district of Rome was then called, which included the Caelian Hill and its foothills. This led to the “obsolescence” of the aforementioned Rivus Herculaneus.

Further expansion of this branch, bringing it to Palatine Hill, the center of imperial Rome, occurred under Emperor Diocletian in the late 3rd century.

The first part of the Arcus Caelimontani can be more or less traced to the foot of the Lateran, while only a few fragments of it remain at Caelius, particularly at the church of Santo Stefano Rotondo. Just behind the church, several high arches of the aqueduct touch where the Porta Caelimontana, one of the gates of the Servian Wall, once stood. In the year 10, two consuls, Dolabella and Silanus, mentioned in the inscription above the passage, restored the arch. After that, the arch was renamed.

Curiously, inside one of the aqueduct’s pillars are two rooms where St. John de Mata (1160-1213), founder of the Order of the Trinitarians or New Crusaders, lived for two years.

The last few fragments of the Arcus Caelimontani can be seen about 200 meters further west, in the valley formed by the Palatine and Caelian hills (segday it is San Gregorio Street running from the Colosseum to the southern end of the Circus Maximus). Here the aqueduct reached its terminus, the complex of imperial buildings on the Palatine. Since this area was quite busy in antiquity, the secondary branches of the Arcus Caelimontani most likely delivered water to the fountains of the Circus Maximus, the institutions along the bank of the Tiber, and others.

Aqueduct on the Via Turati

The short section of aqueduct now crossing the Via Turati belonged to another secondary branch. Its direction points to the nearby ruins of a huge fountain.

This aqueduct is traditionally considered to be a branch of the Aqua Iulia, but its specus height suggests its connection with the Aqua Claudia or Anio Novus.

The above-mentioned ruins of the fountain are now in the garden of Piazza Vittorio Emanuele. This fountain is identified as a nymphaeum built by Emperor Alexander Severus, popularly called “Mario’s Trophies” because of the two sculptural groups adorning it with weapons, shields and armor captured from barbarian tribes as spoils of war (see Ancient Fountains) .

In the 16th century the “trophies” were still in their place. Renaissance illustrations show them near a structure that had already become a ruin. But by the end of the century they had been moved to Capitoline Hill.

Arch of Sixtus V, or Pear Arch

Not far from the Porta Tiburtina gate, the aqueduct with its three water tunnels (Acqua Martia, Acqua Tepula and Acqua Iulia) bends westward, deviating from the straight line followed by the city wall. In fact, it is more correct to say that it is the wall that deviates from the aqueduct, since it was built later. From this point, three aqueducts were already leaving for their castelli, located somewhere in the northern part of Rome. One of them probably stood near the thermae of Diocletian.

What we see today is the aqueduct built in 1587 by order of Pope Sixtus V (1585-1590) on the basis of partially preserved ruins reworked to create a new structure, the Acqua Felice, whose main outlet, or fountain-display, known as the Fountain of Moses, was built 350-400 meters from the former castello.

By the time the Termini train station was built, around 1870, the Acqua Felice itself had become a cumbersome relic. As it passed through the site of this new railroad station, it was mostly dismantled. Only a few meters remain of the Acqua Felice, built from the ancient Acqua Marzia, at the point where it separates from the city wall.

Fortunately, the surviving section includes a “special” double-sided arch built by Sixtus V where the Acqua Felice crossed the Via Tiburtina, the main road to Rome from the east.

The Arch of Sixtus V is similar in shape to another, the Porta Furba. Its upper part contains two large inscriptions:

Sixtus V, Pope,
built with his own money
The Canal Acqua Felice,
flowing underground
13 miles.
Through the arches of the viaduct 7 miles.

And on the other side:

Sixtus V, the pope, paved at his own expense.
Long and wide roads.
On either side (of the arches),
leading to Santa Maria Maggiore
and to Santa Maria degli Angeli.
For the benefit of the people.
And development

It is interesting that the border of the vast estate of the pope’s family was very close to this place, so that in building the aqueduct and roads Sixtus V was guided not only by the benefit of the people, as the inscription says, but also, above all, by his own profit.

The cornerstone of the main arch is decorated with a lion’s head from the pope’s coat of arms, and its edges are decorated with other heraldic symbols of Sixtus V. These are an eight-pointed star (on the north-facing side) and three hills (on the opposite side). The two smaller arches are decorated with pears, referring to the pope’s surname (Peretti – small pears), although not part of his heraldry. For this reason, the structure is also known as the Pear Arch.

Nothing at all remains of the fountain that once stood nearby, welcoming thirsty travelers entering Rome from the east.

Aqua Antoniniana

Just behind Rome’s southernmost gate, the Porta San Sebastiano (originally the Porta Appia, since the Appian Way ran through it), are the ruins commonly called the Arch of Drusa (after the tribune Marcus Livius Drusa, late 2nd century BC). This fragment once belonged to the Acqua Antoniniana, a branch of the Acqua Marcia built by Emperor Caracalla in 212 – 213 for his great baths located in the southwestern part of Rome. It left the main aqueduct at mile 3 of the ancient Via Latina road, roughly where Porta Furba is today, and ran along the southern border of the city.

There are two other minor traces of this branch. One of them is in Piazza Galeria, near the same Porta San Sebastiano. It is a few meters of the upper part of the aqueduct with a tunnel barely visible due to poor preservation. Another trace can be found at the very back of the Terme Caracalla, just in front of where this branch reached its destination.

In Via Guido Baccelli, where it is crossed by Via Antoniniana, along its grassy section on one side stands a series of low arches, now laid down and partially covered with vegetation. These arches also once belonged to Acqua Antoniniana, which made a sharp turn at Porta Ardeatina to reach the baths.

Aqua Claudia, Aqua Martia and Aqua Felice

These three aqueducts can be considered together because of the direction within the city is common. A brief description of each is necessary to understand how they are combined.

The Aqua Martia was the third aqueduct built and the longest of all. It was 91 km long, 90% of which was underground. Aqua Martia was built in 144 BC, and it got its name in honor of the praetor Quintus Martius Rex, who was responsible for the construction.

Aqua Martia water was famous for its purity and good taste. Its springs were located to the northeast of Rome, between modern-day Vicovaro and Subiaco. From Vicovaro, the Aqua Martia ran past the springs of another aqueduct, the Anio Vetus (the second aqueduct that ran completely underground). It then came into contact with Tivoli before turning south and passing through the hills southeast of Rome to enter the city.

Aqua Tepula was built a couple decades later, in 125 BC. Its springs were located in the hills southeast of Rome between present-day Grottaferrata and Marino. It received the name Tepula (warm) because of the temperature of its water, which was 16 – 17 degrees, while the water of the other aqueducts was much colder. An anecdote about Emperor Nero tells how he fainted after bathing in the water of the Aqua Martia in summer.

In the same area, near Lake Albano, had its springs and Aqua Julia, built in 33 BC and named in honor of the family to which Julius Caesar and Emperor Octavian Augustus belonged. Together with the Aqua Tepula, they connected to the Aqua Martia, which already had finished ground structures. Each of them passed through a separate tunnel located respectively in the central and upper parts of the structure.

Aqua Claudia and Anio Novus were built almost simultaneously, from 38 to 52. The first was named in honor of Emperor Claudius, under whose reign the work was completed, and the second – after the ancient Latin name of the river Agnene (Anio), along which it passed. Since an aqueduct with a similar name already existed, it was renamed Anio Vetus (old Anio), and the new one was called Anio Novus (new Anio). Anio Novus was longer than Aqua Claudia (87 km vs. 69 km), as indicated by the inscription above the gate of Porta Prenestina.

Aquae Claudia passed underground for 4/5 of its length, and Anio Novus even more. Their level relative to the ground rose as they approached Rome, and they used the same arches for their tunnels. The upper tunnel belonged to Anio Novus, and the lower one to Aqua Claudia. The height of the arches in some places was simply amazing.

This double and the above-mentioned triple aqueducts approached Rome parallel and very close to each other. The narrow space between them was paved like a road, at least in some sections, and served as a passageway for their maintenance and repair.

The Aqueduct of the Aqua Felice was built several centuries later, during the late Renaissance, with the support of Pope Sixtus V. Therefore, its name is not Latin, but Italian. The pope’s name was Felice Peretti, and the aqueduct was given a name that sounds like “happy water”.

Aqua Felice had a total length of 28.7 kilometers. Its sources were the same as those of the Aqua Alexandrina, but it ran southwest and underground, coming to the surface in the area known as Roma Vecchia (now in the Aqueduct Park), and joining here the course of the aforementioned Aqua Martia and Aqua Claudia, which had by then become ruins. The builders used all the available material from the old aqueducts, i.e. the Aqua Felice literally replaced most of the Aqua Martia and some parts of the Aqua Claudia.

Unfortunately, for this reason, there is little of the Aqua Claudia and almost nothing of the Aqua Martia left in the city area. But the Aqua Felice is preserved throughout, and its arches are easy to distinguish from the ancient structures because they are simpler, have variable column spacing, and are definitely lower than their predecessors.

To see the older sections, one can use the Aqua Felice as a mythological Ariadne’s thread, following it to the distant suburbs, where substantial parts of the Aqua Claudia and parts of the Aqua Martia are still preserved.