The Castra Albana [ˈkastra alˈbaːna] was an ancient Roman legionary fortress of the Legio II Parthica founded by the Emperor Septimius Severus (193–211) on the site of the present Albano Laziale.

Today the remains of building both inside the castra and in the neighbouring civilian settlement, such as the so-called Baths of Caracalla and the Amphitheatre, can still be seen.

[4] and perhaps of Pompey the Great (in the Villa Doria)[5][6][7] Nevertheless, until the time of Domitian, the stretch of the Appian Way between Bovillae and Aricia (modern Frattocchie in Marino and Ariccia) was completely free of buildings.

[8] In the Republican period, the area of the later castra was occupied by fortifications remains of which were found at various points in central Albano Laziale.

[9] The castra was built in about 198 by Septimius Severus (193-211) who came to the throne after the Year of the Five Emperors and a violent civil war and temporarily dissolved the Praetorian Guard and brought the Legio II Parthica near Rome for his personal and political security.

[2] When Caracalla (211-217) came to power after assassinating his brother and co-emperor, Geta, the Legio Parthica refused to accept him as sole emperor.

[16] He went in person to Castra Albana and convinced the legion to remain loyal increasing their stipend by 50%[17] and improving the camp by having the Baths of Caracalla built.

[2] The amphitheatre was built in the middle of the 3rd century and could mark the end of the period of highest prosperity for the Legio II Parthica which may no longer have been there.

Constantine I (306-337) founded the Cathedral of San Giovanni Battista at Albano Laziale during the pontificate of Pope Silvester I (314-335), providing it with decorations and substantial property nearby,[19] including the sceneca deserta vel domos civitatis (the abandoned tents or the houses of the city).

On the same street, the well-conserved remains of a circular guard tower can be accessed, 3.4 m below the modern ground level of the Via Alcide de Gasperi.

The circular room inside the convent, described before the war, had a diameter of 3.6 m and was covered by a low dome of very poor workmanship, probably a modern repair.

A well-preserved stretch of about fifty metres serves as the boundary wall between the episcopal seminary and the Missionaries of the Precious Blood, which govern the church of San Paulo.

[28] Past the Via San Francesco d'Assisi, on which the Medieval gate of the Cappuchins opened until the second half of the Nineteenth century,[28] the wall follows the Via Tacito, on the property of the Daughters of Immaculate Mary.

[29] Turning onto the Via Castro Partico sixty metres from the rounded corner,[30] the wall contains a rectangular guard tower, currently put to use as a farmhouse.

The gate, considered one of the most beautiful remnants of the castra by the archaeologist Giuseppe Lugli,[31] consisted of a single archway 3.8 metres wide.

[32] The wall then proceeded along the line of the facades of the houses on the south side of the modern Via San Gaspare del Bufalo, passing the sixteenth century Trident of the streets, and ending at the modern piazza San Paolo, where some remains were found during some hydraulic work in 1904, arranged in horizontal layers to deal with the steep slope of the terrain.

[33] In the 1980s excavations carried out by the Museo civico of Albano Laziale and the Ramacci company on the site of a demolished seminary on Castro Pretorio Street discovered the intersection between the via principalis and one of roads running parallel to the via praetoria.

[38] The building structure is made up of a core of peperino gravel cement, broken up by stretches of brickwork and faced with mattone bricks.

[40] The southern half of the amphitheatre is visible, while the northern part is buried under the retaining walls of San Francesco d'Assisi St and Anfiteatro Romano Street.

The first theory would explain the paviment of white and black mosaic tesserae with mythological figures, today located in the portico of the church.

But the archaeologist Giuseppe Lugli discovered a second, more ancient tunnel on the same side, which served the cistern through a complex system until it broke.

[33] The sewage network of the castra must have been extensive and would have followed the slope of the hill, discharging into the main sewer running under the intervallum in Alcide De Gasperi Street.

The first discoveries near Selvotta, a place on the borders between Albano Laziale and Ariccia, were made in 1866 by a farmer called Lorenzo Fortunato and were analysed by the young Russian archaeologist Nicola Wendt.

[55] The German archaeologist Wilhelm Henzen was the first to suggest that the frequent references to the Legio II Parthica found in the inscriptions discovered at Selvotta would have to indicate a necropolis of the legion, located a short distance from the castra.

[55] A campaign of excavation and surveying in the area was carried out by Henzen, Hermann Dessau, and Rodolfo Lanciani at the end of the nineteenth century.

[56] From analysis of the grave inscriptions it is clear that the greater part of the soldiers bore the praenomen Aurelius and therefore it is deduced that they served in the time of the legion's greatest prosperity, during the reigns of Caracalla (211-217) and Elagabalus (218-222).