sentences:  the embassy of Zemarchus) with the Gokturks for an alliance against Persia; in 570, the Sassanids invaded Yemen, expelling the Byzantines' Aksumite allies and restoring the Himyarite Kingdom as a client state; in 570 and 571, the Sassanids' Arab clients, the Lakhmids, launched raids on Byzantine territory, although on both occasions they were defeated by the Ghassanids, clients of the Byzantines; and in 570, the Byzantines made a secret agreement to support an Armenian rebellion against the Sassanids, which began in 571, accompanied by another revolt in Kingdom of Iberia.Early in 572, the Armenians under Vardan II Mamikonian defeated the Persian governor of Armenia and captured his headquarters at Dvin; the Persians soon retook the city but shortly afterwards it was captured again by combined Armenian and Byzantine forces and direct hostilities between Byzantines and Persians began.Despite frequent revolts in the 5th century, during the earlier wars of the 6th century the Armenians had largely remained loyal to their Sassanid overlords, unlike their neighbours and fellow Christians in Iberia and Lazica (Colchis).