A good popular history of the other side of the "Fall of the Roman Empire" is "Terry Jones' Barbarians".
I scare-quote "Fall of the Roman Empire" because even though Rome itself was sacked, the Eastern half of the Roman Empire kept going for another millennium, though known to us moderns as the Byzantine Empire (it was known to all contemporaries merely as The Roman Empire).
I scare-quote "Fall of the Roman Empire" because even though Rome itself was sacked, the Eastern half of the Roman Empire kept going for another millennium, though known to us moderns as the Byzantine Empire (it was known to all contemporaries merely as The Roman Empire).