The Quran Verse
Surah 30:2–4
The Romans have been defeated (ghulibati) in a nearby land. But they, after their defeat, will be victorious (sayaghlibūn) within a few years...
The Historical Context
In the early 7th century, the Byzantine (Roman) Empire was being crushed by the Sassanid Persians. By 614 AD, the Persians had taken Jerusalem and even captured the "True Cross." To the Meccans, the defeat of the Christian Romans was a sign that the pagan Persians (and by extension, the Meccan polytheists) would triumph over the monotheistic Muslims.
The early Quranic manuscripts lacked vowels and diacritical marks, the words ghulibati (were defeated) and ghalabat (defeated) look identical in the rasm (consonantal skeleton).
Critics argue that this variant likely refers to the Battle of Mu'ta or the later Muslim conquests where the Muslims defeated the Romans. If the text originally predicted a Roman defeat by Muslims, but was later "re-voweled" to look like a prophecy of a Roman victory over Persians, then the "miracle" is actually a result of post-hoc scribal editing to fit historical events.