After blobbing hard as Italia, I saw that there was a claimant to Byzantium with a strong claim who would actually come to my court. I invited him, betrothed his daughter to my son, and pushed his claim. As he was celebrating his first year as Emperor, I was also plotting to kill him so his daughter would become Empress.

I successfully assassinated him without being caught, and she was now empress. I kind of lucked out because the empress died in battle against the Germans (who exist because I got a "Religious Liberation" CB on the HRE like 100 years ago). Then my character died, and my new character died of pneumonia soon after.

After he died and I inherited the empire of Italia (everything in the empire other than Greece, Trebizond, and the Balkans), restored the Roman Empire, and mended the schism after revoking Rome, assassinating a few bishops so their replacement would be Orthodox and the holy sight would be held by an Orthodox patriarch, and crushing a few Catholic revolts.

Oh, my emperor is also a descendant of Muhammad (sadly no trait) and my previous emperors have Arab portraits because I married a Hashimid princess who grew up under house arrest in Italy and was raised to become an Italian Catholic, but the Hashimids are my loyal vassals and were given the Kingdom of Arabia and the Kingdom of Yemen. My next emperor will also be a descendant of Genghis Khan since I'm married to a Yuan princess.