The Via Appia, the “Regina viarum” (Queen of the roads), was one of the oldest and most prestigious consular roads of the Roman empire. Since it was not allowed to build tombs within the city walls, the most important figures of ancient Rome chose this and other large consular roads to build their tombs.
The aristocrats competed in building increasingly larger and monumental tombs: it was a way of showing everyone the wealth and importance of their family (the Gens).
One of the best known is the Mausoleum of Caecilia Metella, which is well preserved because in the Middle Ages it was transformed into a defensive tower by the Caetani.
Since the time of the Etruscans, aristocratic families had built large tumulus tombs to remember their ancestors. To distinguish themselves from the common people, they claimed to be descendants of an important figure, who gave them the "quarters of nobility" and was often linked to the myths of Greek heroes such as Heracles. A form of semi-divine legitimation of power that was maintained by the Romans.
In 309 AD, Romulus Valerius, son of the emperor Maxentius, died at only fifteen years old and in mysterious circumstances. He was immediately deified and his father dedicated a Temple to him in the Roman Forum (the church of Saints Cosmas and Damian). In 310 AD the emperor decided to build for him a grandiose Mausoleum right along the Appian Way, not far from that of Caecilia Metella.
Next to the Mausoleum, Maxentius built a large Circus where funeral games were held in honor of his son. At that time, the Roman Calendar included sixty-five days dedicated to various Circus Games (Ludi Circenses), which the emperor watched from a royal box reserved for him, called the Imperial Pulvinar, which is still visible on one side of the circus itself.
Near the Carceres of the circus - the structures from which the quadrigas of the races started - the emperor built an imposing square enclosure, with eleven-meter-high walls. It delimited the sacred area (the temenos) that surrounded the Mausoleum, separating it from the profane space.
The same thing happened in the Mausoleum of Hadrian, which was surrounded by a square enclosure with a gate that separated it from everything else; and in genera an enclosure surrounded all tombs of a certain importance.
The main entrance to the enclosure opened onto the Via Appia and from there the Mausoleum was reached via a staircase that went up to a pronaos with columns, which was later transformed into the Casale Torlonia. An inner door gave access to the actual tomb, of circular shape (diameter of about 33 meters) which has a ring corridor whose barrel vaults rest on a large central pillar.
Because of endless alterations and the plundering of all the ancient materials it is difficult to have a reconstruction based on actual evidence; some scholars even thought that the building imitated the Pantheon and that above the circular tomb there was a second floor with a dome like that of the Pantheon, which is quite unlikely.
In the walls of the tomb there are eight niches alternately rectangular and semicircular. Six of them have window-tunnels that open outwards, while along the main axis there are two doors: one is towards the pronaos-Casale oriented to the south-west, perfectly in axis with the main door of the facade. The other is a rear entrance oriented to the north-east, on the opposite side.
In 2020 we were contacted by Professor Roberto Brunelli from Rome, because on December 26, 2019 he had visited the Mausoleum of Romulus, taking a photograph of the Sun setting in axis with the main door of the building.
He asked us if there could be a connection with the Winter Solstice and in particular with the cult of Sol Invictus, adding that he had given the photograph a different meaning thanks to our archaeoastronomy studies seen on the Internet.
According to the calculations of the archaeoastronomer Giuseppe Veneziano, the door of the main facade (southwest) is oriented at 228°23', so as to make it coincide with the sunset on the days of the Winter Solstice (December 21); this takes into account the so called local horizon, that is, the height of the surrounding wall that makes the Sun set a little earlier and with a different azimuth. This confirms the initial hypothesis of an illumination or hierophany intentionally planned.
The date of the illumination had an important symbolic meaning: on the days of the Winter Solstice (December 21), as is known, the Saturnalia were celebrated, with rites of passage from the old to the new year. Starting from the 3rd century AD, the Saturnalia were merged with the Dies Natalis Solis Invictus, a new celebration that commemorated the birth of that solar divinity on December 25th.
That oriental cult had been imported to Rome for the first time by the emperor Elagabalus (or Heliogabalus) in 218 AD, and abandoned upon his death in 222. It was reintroduced by Aurelian in 274 AD who made it the official State cult.
The emperor Diocletian also identified himself with the Sol Invictus and proclaimed to be divine already during his lifetime – dominus et deus (lord and god). In the Vestibule of his Palace in Spalato (Split, Croatia) we discovered hierophanies that occurred precisely on the days of the summer and winter Solstice and were a manifestation of the emperor's divinity and power.
Maxentius too had good reasons to associate himself with the cult of Sol Invictus. His story is set in the turbulent era of the succession of Diocletian and Maximian, the two Augusti of the Tetrarchy who abdicated in 305 AD.
As expected, they were replaced by the two Caesars, Galerius and Constantius Chlorus, but upon the death of the latter, the army of Gaul and Britain proclaimed Constantine Augustus (the illegitimate son of Constantius Chlorus, who had no right to power), while in Italy the Praetorians proclaimed Augustus Maxentius (the legitimate son of Maximianus) on October 28, 306.
To settle things with diplomacy, Maxentius' sister married Constantine in 307; and on April 21, 308 AD – another significant date because it was the Dies natalis of Rome – Maxentius proclaimed himself the legitimate Augustus, but was never recognized by the Senate.
To legitimize the succession and his power, he created a divine ancestry "in reverse", deifying the dead son. The illumination (hierophany) that occurs in the Mausoleum of Romulus on the days of the winter Solstice and Sol Invictus was a sacred sign of his deification and gave Maxentius a divine legitimacy of his power, bypassing the Senate that did not recognize his right to power.
The hierophany belonged to a centuries old tradition, because it has an illustrious precedent in the Mausoleum of Hadrian, who was depicted there as Sol Invictus driving the Quadriga of the Sun. In the Hall of the Burial Urns during the summer Solstice some illuminations are still visible, which we discovered and published in the book «Castel Sant'Angelo. Mausoleum of Hadrian. Architecture and Light» also in English edition.
It is likely that the Mausoleum of Romulus was conceived as a new imperial dynastic Mausoleum, given that the Mausoleum of Hadrian (Castel Sant’Angelo) was almost two hundred years old and perhaps there was no more room inside it for other burials.
The reign of Maxentius, however, lasted for few more years until 312 AD, when he was defeated by Constantine in the famous battle of Ponte Milvio or Saxa Rubra, at the gates of Rome.