Planet of Hats
Donor
The butterflies from Byzantium falling to the Arabs are impossible to predict in more than broad strokes because of the sheer magnitude of the event but I can see the Pope taking on an outsized role early on. This is at the height of the Byzantine Papacy and all the Popes since the 600s have had ties to Constantinople, and depending on the POD, Leo the Isaurian hasn't quite had time to annoy the Pope yet. It's pretty much a given that the Papacy would try and rally support to Constantinople, probably with a certain amount of success. You may end up with a stronger Papacy earlier. Odds are the iconoclasm gets butterflied - the Emperor probably has other things on his mind than icons right now.
Basically how I found all the stuff I needed for the TL I'm working on!I've learned to give up on the search function and just use google search to find threads on here. Though that doesn't work for the hidden forums.