An astonishing revelation that the Qur'an gives about the future is found in Sura Rum, referring to the Byzantine Empire, the eastern Roman Empire. In these verses it is stated that the Byzantine Empire had met with a great defeat, but that it would soon gain victory:
Alif, Lam, Mim. The Romans have been defeated in the lowest land, but after their defeat they will themselves be victorious in a few years' time... (Sura Rum, 1-4)
This was revealed around 620 CE, seven years after the defeat of Byzantium by the Persians. Yet the verses stated that Byzantium would shortly be victorious. Byzantium had suffered such heavy losses that it seemed impossible for it even to survive, let alone be victorious. Not only the Persians, but others posed serious threats to it. The empire was on the point of collapse. Many areas were invaded by the Persians.
Everyone was expecting the Byzantine Empire to be destroyed. But at that moment, the verses of Sura Rum were revealed, announcing that Byzantium would triumph. This seemed so impossible that Arab polytheists made fun of these verses.
Around seven years after this, in 627 CE, a battle between Byzantium and the Persian Empire was fought. And this time the Byzantine army unexpectedly defeated the Persians. Later, the Persians made an agreement, obliging them to return the territories they had taken.
"The victory of the Romans," Allah proclaimed in the Qur'an, miraculously came true.