 They later established relations with the Sassanid Persian and Byzantine empires.Though traditionally allied with the Sassanids' Lakhmid clients, the Tayy supplanted the Lakhmids as the rulers of Al-Hirah in the 610s.In the late 6th century, the Fasad War split the Tayy, with members of its Jadila branch converting to Christianity and migrating to Syria where they became allied with the Ghassanids, and the Ghawth branch remaining in Jabal Tayy.