The Persians invaded the Roman (Byzantine) empire and sacked Jerusalem and killed most of the Christians there in 614, something that is mentioned in the Koran.
and this military history site adds:
When the Persian conquest of Palestine took place in 614 CE, no one
could have foreseen the long range consequences of this event. However,
with hindsight it becomes evident that this was a major turning point in
the history of the Near East. The brutalities of the invading armies,
involving large scale damage to churches and a mass killing of the local
Christian population, was undoubtedly one of the causes for the rapid
Muslim conquests, twenty years later.