When Arab armies moved out of Arabia in the 630s and utterly wrecked the Roman-Persian balance of power that had defined western Asia for centuries, you could make a strong case that nobody, apart from the Romans and the Persians, felt it more acutely than the Armenians. The Kingdom of Armenia had long been a buffer between the two great powers, with dynasties ruling as Roman or Persian (first Parthian, and later Sasanian) clients, and coming and going often at the whim of one of the two empires. This changed in the fourth century, when the Romans and Sasanians partitioned the ancient kingdom into two parts: so-called Lesser Armenia, which became a Roman province, and Persian Armenia, which held nominal independence for a time before becoming a Sasanian domain in the early fifth century. The events described here primarily affected Persian Armenia; Lesser Armenia, along the southern coast of the Black Sea, remained in Roman hands until it was taken by the Seljuq Turks in the late 11th century.
Having suffered through the push-and-pull Roman-Persian relationship for the better part of a millennium, the Armenians now had to face a new upheaval with the destruction of the Sasanian Empire and the arrival of conquering Arab armies in the Caucasus as early as the late 630s, not even a decade after Muhammad’s death.