Zaldapa

Zaldapa was a major Late Roman fortified city in Scythia Minor, covering approximately 35 hectares near modern Abrit in northeast Bulgaria. Originally a Thracian settlement from the 8th century BC (its name meaning 'yellow water'), the fortress walls were probably built in a single campaign during the late 4th century AD. The defences included 32 towers, three main gates, and two secondary gates, with a 3-metre-wide secret tunnel connecting a water reservoir to the fortress interior. Excavations since 2014 have uncovered a Roman civic basilica (101 by 18 m), an early Christian basilica, and a bishop's basilica, confirming Zaldapa as a major regional centre of Christianity in the 6th century.