THE BATHS OF DIOCLETIAN EXPLAINED
Welcome to the Baths of Diocletian page, where I explore the largest bathing facility in the whole Roman Empire. Built in 306 AD, this luxurious and enormous Imperial Roman Baths served 10,000 people daily for 250 years. Much of this facility still exists, and it has been transformed into museums, gardens, and a stunning Basilica designed by the great Michelangelo himself. Entering this basilica is almost like entering the Baths of Diocletian when it was at its prime and covered in glistening marble and ornate decoration.
The image above shows the large scale of the main baths building that was surrounded on all sides by gardens and walls containing many kinds of structures. Furthermore, the Baths of Diocletian was so huge that its outside swimming pool - the Natatio - was three times the size of an olympic pool and featured beautiful sculptures along the walls, as shown in the drawing below.
Romans enjoying Baths of Diocletian Natatio pool in 320 AD
I will look at the history, architecture, art, and many other aspects of this ancient bathing complex. And though some parts of the Baths of Diocletian have vanished, nevertheless, the vast ruins, thick walls, and spaces that exist today are still impressive and monumental.
Baths of Diocletian in 306 AD compared to 2021 AD.
INTRODUCTION
In 306 AD, with the completion of the Baths of Diocletian, Roman baths reached their peak not only in size but also in luxury. Even today, the current basilica inside the former ancient Frigidarium is still one of the most exhilarating interior spaces in the entire city of Rome.
This bathing facility was designed so that 3,000 bathers could use its facilities at the same time for a total of 10,000 every day. The location of the Baths is the Viminal Hill, the smallest of the seven hills of Rome.
This colossal building complex was a larger version of the already vast Baths of Caracalla, which opened 90 years earlier in 216 AD. When you stand in its centre, you can understand why, long after the Roman empire had fallen, people once thought that giants had built Rome.
Built of concrete and millions of bricks, the Baths of Diocletian was decorated lavishly with marble walls and floors, hundreds of columns, frescoes, mosaics, numerous statues, and large upper windows that filled the interior with sunlight.
Furthermore, the size of these baths, including the surrounding outside gardens, walls, and other structures, measured 13 hectares (32 acres). The actual main baths building itself was an incredible 4.5 hectares (11 acres) in size. One can only marvel at the labour, resources, expertise, artistry, and planning required to build such a massive complex in only eight years (298 - 306 AD).
Baths of Diocletian Main Hall in 4th century
From floor to ceiling was seven storeys in height
From a drawing by Edmond Jean-Baptiste Paulin, 1880, Modified
In ancient times, undoubtedly the Baths of Diocletian complex was an outstanding sight with its vast spaces, marble-covered walls, beautiful mosaics, statues, and frescoes. The image above aptly shows how massive this bathhouse was, and this is just a partial view of the Main Hall showing parts of the Frigidarium and Tepidarium areas.
Notice how the high, vaulted ceilings cover a considerable area of marble floorspace below. This high ceiling's vaults are supported by eight huge columns made of red granite from Egypt, and they are still there supporting the original ceiling today. These columns are 17 metres high (56 feet) and 1.6 metres wide (5 feet).
The incredible amount of detail and decoration you see displayed throughout the drawing above was typical of Roman design, which loved splendour and luxury. There is a pool on the left and right sides with an even larger pool in the distance. There are also large "tubs" at various locations on the floor. And, like many large Roman buildings, the brick superstructure was covered with marble on the inside and white stucco on the outside.
Baths of Diocletian interior Main Hall in the 21st Century
In the image above, we see the same Main Hall of the Baths of Diocletian as it looks in the 21st century (2008). The view is of the same large, arched passageway on the right side of the fourth-century drawing above the photo. Amazingly, those reddish-granite columns and capitals (as well as the ceiling) in the drawing have miraculously survived a 1,700-year journey through sackings, wars, pillaging, earthquakes, and neglect.
If you think that the photo above looks like the inside of a church, you are correct. In the 16th century, this church was designed by the great artist and architect Michelangelo. He built this church (basilica) while using as many of the original materials as possible, within the ancient Frigidarium and Tepidarium, of the Baths of Diocletian.
During the work, the floor was raised 2 metres (2 yards) because the outside ground level had risen over the centuries. Moreover, the entrance to this church - which is actually a basilica - is through what remains of the former circular Caldarium, shown in the image below. When people pass through the doors of this basilica, they are entering the former Tepidarium section of the baths, which has a magnificent dome with a hole (oculus) in its centre. This dome is a smaller version of the great dome found in the Pantheon.
Entrance to St. Mary of the Angels & Martyrs Basilica
The rounded entrance is part of the ancient Caldarium
Image courtesy of Justin Ennis - CC BY 2.0
As you can see, most of the Caldarium entrance is now gone. And though the entrance may look very worn and damaged, the interior of the church is actually stunning and quite beautiful. The bluish doorway on the left is part of the western section of the Baths used as a granary, an orphanage, and a poorhouse for women.
The basilica entrance faces south towards a large plaza called the Piazza della Repubblica built in 1898. This entrance changed drastically in appearance from 1749 to 1911 AD, which I will discuss in detail later.
THE NAME AND HISTORY OF THE BATHS OF DIOCLETIAN
Built during the years 298 to 306 AD, an interesting fact about these baths is that they were not built by Roman Emperor Diocletian (244 - 311 AD) at all. In fact, by the time the baths finally opened, he was no longer an Emperor.
Diocletian may never have seen these baths because he did not live in Rome; instead, he lived his entire life in the Eastern Roman Empire, where he was born in present-day Croatia. However, because he visited Rome in the year 303 AD for the 20th anniversary of his rule, he may have looked at the bathhouse while it was still being constructed.
 |
 |
The person who commissioned and built the Baths of Diocletian was Emperor Maximian, who co-ruled the Roman Empire with Diocletian. They both ruled the Roman Empire from 286 to 305 AD, although Diocletian was an Emperor starting in 284 AD.
The Western half of the Roman Empire, where Rome was located, was ruled by Maximian and the Eastern half was ruled by Diocletian. Despite this division, the empire was not really split. It just got so big that it was too much for one Emperor to handle. This arrangement was similar to when the Roman Empire was co-ruled by Octavian (Augustus) in the West and Marc Antony in the East for ten years after the death of Julius Caesar in 44 BC/BCE.
An interesting fact is that, before the baths were completed, both Maximian and Diocletian abdicated in the year 305 AD, the only Roman Emperors to willingly do so. However, while Diocletian never became an Emperor again, Maximian came out of retirement quickly and tried to take power a few times before being forced to commit suicide by Emperor Constantine the Great.
It is said that thousands of enslaved Christians - possibly 40,000 or more - did the hard work of building the baths. It is possible Christians were used as slaves because Emperor Diocletian was hostile towards Christians and instigated policies that persecuted them. And that is why there is a church within the ruins dedicated to Christian martyrs who died while building the baths.
ROMAN BATHS SIZE COMPARISON
The alternating diagrams below show the outlines of the Baths of Diocletian and the Baths of Caracalla, so you can compare them. You will see that the main building of the Baths of Diocletian was larger. However, you will also notice many similarities such as:
| • |
Both had the same basic arrangement
of bathing pools (Frigidarium, Tepidarium, Caldarium, Natatio), exercise courts (Palestrae) and changing
rooms (Apodyteriums).
|
| • | They were both surrounded by gardens, fountains, pools, and a wall containing towers and exedrae (plural of exedra). |
Another shared characteristic is that both these baths were built mainly of bricks and concrete covered with a marble veneer on the inside and white stucco on the outside.
In the diagrams below, please note that, although the Baths of Diocletian main building is 20% larger, the Baths of Caracalla complex (building and surrounding gardens, walls, etc.) occupied a more extensive area - 25 hectares (62 acres) versus the Baths of Diocletian's smaller 13 hectares (32 acres).
Notice how the Baths of Caracalla has large and circular exedras on the lower left and right sides of its outside wall. In comparison, the Baths of Diocletian, in addition to its huge bottom theatre exedra, also has numerous circular and rectangular exedras all along the other three surrounding walls.
The semi-circular exedras are said to have a "hemicycle" shape, meaning semi-circular. The arrangement of the water pools is precisely the same. In addition, both baths have two Palestrae (exercise area) areas, one on either side of the Frigidarium water pool.
THE BATHS OF DIOCLETIAN WERE THE LARGEST EVER BUILT
The moving panorama below shows the Eastern facade and then the Western facade of the Baths of Diocletian in the fourth century when the whole structure was standing. These baths were enormous and covered a vast expanse of ground estimated at 140,000 square metres (1,500,000 sq. feet). The highest point of these buildings, the Main Hall in the centre of each facade, was over 30 metres (100 feet) high. As you watch the facades of these baths scroll by, keep in mind that a person standing next to these buildings would appear tiny.
