Verses 2-5, Chapter 30 in the Quran state:
“The Romans have been defeated at the nearest/ lowest land but they will gain victory within a few years. Allah has the Command in the former case and in and will be pleased with the victory of God. He helps to victory whom He Wills. He is the All Mighty, the Merciful”
At Muhammad’s time, it is virtually impossible for Arabs to predict how the development of the conflict would be between the two superpowers (at their time) within the next ten years and whether a defeated empire can restore victory within a few years. It is a historical fact that the Persian Empire defeated the Roman Empire in the period (614-619 CE) in Palestine area and captured Jerusalem. But within a few years, the Romans had restored victory over the Persians at Nineveh (a city in Iraq).