[Quranic Reflection]: (2) The Romans have been defeated

[Deesse23]

I think this is the right interpretation "Rum" refers to Rome -either Eastern or Western; the word is not specific to an empire-, while "Byzantine" is specific to the Eastern Empire.

Its not possible that the Quran is talking about the Byzantine Empire, which was a contemporary of the people writing the Quran?
How do you know the sura refers to the downfall of the Byzantine Empire some 800 years later, and not to the current, ongoing war with the Sassanid Empire?
Does the Quran say "the Romans WERE defeated" or does it say "the Romans WILL BE defeated"?