Being a vassal meant that I didn't have to put as much thought into external factors and could just focus on home soil, the ruling family became Greek and Orthodox, to fit in with the empire (and get the options to blind/castrate prisoners). I went into a game of CK2 with the intention of starting from beginning to end, I wanted a fairly relaxed run so planned to just play as Lombardy (to become Italy) as a vassal of the Byzantine Empire.