commercial centres were built by Kings Artaxias I, Artavasdes I and Tigranes the Great. Thus, with the dominance of cities such as Artaxata and Tigranocerta, Erebuni had significantly lost its importance as a central city. Under the rule of the Arsacid dynasty of Armenia (54–428 AD), many other cities around Erebuni including Vagharshapat and Dvin flourished. Consequently, Erebuni was completely neutralized, losing its role as an economic and strategic centre of Armenia. During the period of the Arsacid kings, Erebuni was only recorded in a Manichaean text of the 3rd century, where it is mentioned that one of the disciples of the prophet Mani founded a Manichaean community near the Christian community in Erebuni. According to Ashkharatsuyts, Erebuni was part of the Kotayk canton (Կոտայք գավառ, Kotayk gavar, not to be confused with the current Kotayk Province) of Ayrarat province, within Armenia Major. Armenia became a Christian nation in the early 4th century, during the reign of the Arsacid king Tiridates III. Sasanian and Roman periods Following the partition of Armenia by the Byzantine and Sasanian empires in 387 and in 428, Erebuni and the entire territory of Eastern Armenia came under the rule of Sasanian Persia. The Armenian territories formed the province of Persian Armenia within the Sasanian Empire. Due to the diminished role of Erebuni, as well as the absence of proper historical data, much of the city's history under the Sasanian rule is unknown. In 587 during the reign of emperor Maurice, Yerevan and much of Armenia came under Roman administration after the Romans defeated the Sassanid Persian Empire at the battle of the Blarathon. Soon after, Katoghike Tsiranavor Church in Avan was built between 595 and 602. Despite being partly damaged during the 1679 earthquake), it is the oldest surviving church within modern Yerevan city limits. The province of Persian Armenia (also known as Persarmenia) lasted until 646, when the province was dissolved with the Muslim conquest of Persia. Arab Islamic invasion In 658 AD, at the height of the Arab Islamic invasions, Erebuni-Yerevan was conquered during the Muslim conquest of Persia, as it was part of Persian-ruled Armenia. The city became part of the Emirate of Armenia under the Umayyad Caliphate. The city of Dvin was the centre of the newly created emirate. Starting from this period, as a result of the developing trade activities with the Arabs, the Armenian territories had gained strategic importance