I’ve read the arguments about the people who destroyed Jerusalem and the Temple being Assyrians. How can we be sure they weren’t?
First of all, Assyria didn’t exist at the time, but the soldiers’ actual nationality doesn’t matter. What matters is whether they were fighting as Romans, under Roman authority. It matters because Daniel 9:26 says that the anti-Christ will come from the people who destroyed the city and the sanctuary.
Josephus recorded the speech of General Titus Vespasian, son of the Roman Emperor, on the eve of the final Battle for Jerusalem. Here’s part of what he said:
“It is unbecoming of you, who are Romans and my soldiers, to be inferior to Jews, either in action of the hand, or in courage of the soul.”
The Roman general who commanded them and who was following the orders of the Roman Emperor addressed them as Romans. It was the Roman Army that destroyed the city and the Sanctuary.