"20. redhouse mutes Synapse"
Sorry but that's really further down the line.
"My greek/roman/medeival history isn't very good, so I'm hoping someone can fill some gaps here as well. I'm good from about 1650 to 1945"
Ok, not entirely sure about all of this, but:
20. Romans kick ass, conquering the Meditteranean
21. Barbarians coming from the East (Huns and Vandals?) causing fear among other tribes and such, causing a chain reaction all through Europe.
22. There have been loads of rebellions/civil wars in the Roman Empire, with people fighting to be the next emperor and such. At some point the Roman Empire is permanently split into Western and Eastern Roman Empire (which don't fight eachother as far as I know, and may still be allied, but they are ruled by separate leaders, and act as such.
23. The Western Romans (in particular) can't withstand the hordes of barbarians which were driven their way (by Vandals and Huns, later Goths, and there are numerous other tribes, who all feared the arrival of other tribes, and only few stood to fight, and usually died sooner or later) searching for new homelands in France, Spain and Italy (which is most of the Western Roman Empire at that point) combined with the pretty much continuous rebellions/civil wars there, (there was a new emperor every year/few years) and so the Western Roman Empire fall pretty rapidly, the capital (Rome, duh!) being sacked at least once by the Vandals, but it could have been sacked a few times, I don't remember if the Romans ever managed to rebuild it after that. Anyway, Western Roman Empire was dead.
I think the Eastern Roman Empire lived on (as the Byzantine Empire I think? Pretty much just a change of name though, I think? But that is more of an assumption to be honest) very long, Constantinople was sacked in 1453 if I remember correctly, while the Roman Empire split in 363 A.D. if I remember correctly, and the Western Roman Empire died around 400 A.D. I'm guessing. That's not exactly the first thing to happen after the fall of the Western Roman Empire, so it's not number 24.
I think 24 is the barbarians settling down, doing the landheir-stuff, they pay for protection and the right to use lands of others, if they are of others, and this sytem gets bigger and bigger and I think the Franks are one of the first few to establish a kingdom again after that (that'd be 25, IF I'm right)