Dvin is situated on a hill where a settlement, turned into a fortress in the antique epoch, it was found in the third millennium B.C. In the reign of Khosrov II (330-338) Dvin became the capital, and since the middle of the fifth century till the middle of the 13th century, it was a major trade, handicraft and cultural center of Armenia known in the countries of Asia Minor and Europe.
Excavations revealed the layout of Dvin which followed the pattern of Armenia's ancient fortified settlements. Double town walls were fortified with large round towers, and the citadel had a moat around it.
The rulers palace was situated on the top of a high hill which dominated the town, inside a vast citadel. The rectangular-base building was a two-storey one, with richly decorated presence and residence chambers in the first floor, and service premises, including a bath-house with men’s and women’s sections equipped like that in Garni, in the ground floor. This palace, just as the palaces of feudal lords (nakharars) and the suburban palace of King Khosrov II in the valley of the Azat river, are the pride of Armenian historians who say they are no doubt among the best civil buildings of fifth-century Armenia.
The palace of Katholikos - the head of the Armenian clergy - was in the central neighborhood to the west of the citadel, among the monumental stone structures of the city which formed one of the prominent architectural ensembles of Armenia of those times.
The ruins of Katholikos’ palace - an imposing edifice built in the 7th century - are very impressive. The front part, built under the influence of the architecture of the Armenian peasant home, had as its nucleus the central hall (11.4 by 26.7 m) with two rows of columns, with rectangular rooms adjacent to its lateral sides. Stone columns with the base shape of the antique type were crowned with eye-catching volute-like capitals. Their face side is adorned with coiled palm leaves, with two others rising from between them, as if from the column shaft.
The architecture of Catholicos’ palace in Dvin played a great role in the development of civil architecture in Armenia in early feudal times. A small vaulted church of 553-554 was situated east of the Katholikos’ palace in Dvin. The vestibule and a five-arc gallery on the northern side make it possible to date it back to the fourth-seventh centuries when the temples of this type were built in Armenia.
St.Grigory Cathedral was more monumental and Armenia’s biggest one (30.41 by 58.17 m). Built in the third century as a three-nave heathen temple with seven pairs of inner supports, it was rebuilt in the fourth century into a Christian church. In the middle of the seventh century the cathedral was rebuilt into a cross-winged domed temple with apses protruding on the lateral facades.
The altar apse was decorated with a mosaic of vari-colored cubes of smalt and tufa representing the Holy Virgin (the 7th century). That was the most ancient mosaic depiction of the Holy Virgin on the territory of Armenia.