When did the Rome's collapse happen?

Answer 1

It was not Rome which collapsed. It was the western part of the Roman Empire The conventional date set by historians for the end of the western part of the Roman Empire is 476. In this year the last emperor in the west, Romulus Augustus was deposed.

The western part of the Roman Empire fell under the weight of the invasions by the Germanic peoples. The eastern part of the Roman Empire was not affected by these invasions and continued to exist for nearly 1,000 years. Historians call it Byzantine Empire. This is a term which has been coined to indicate the eastern part of the Roman Empire after the fall of the western part. The Romans did not use this term, they called it Roman Empire or Romania (this referred to this empire and not the country which was later called Romania).