The Castellum contra Teutanum fort (known earlier as Contra Aquincum) stood on what is now Március 15 Square.
The area around the Pest side of Erzsébet Bridge was an important river crossing point in Roman times. In the 4th century, a fort with a slightly diamond-shaped plan, measuring 84 x 86 metres and with walls about 3.5 metres thick, was built here. It is possible that the crossing may have been protected by a military installation as early as the 2nd century AD, but there is no archaeological evidence for this at present.
The fort, located on Március 15 Square, was formerly known as Contra Aquincum. Recent research, however, indicates that the ancient name of the fort would have been Castellum contra Teutanum. The name Contra Aquincum can be applied to the fort at the mouth of the Rákos stream, previously known as Transaquincum.
