Basilica di San Vitale
This ancient mosaic inside Basilica di San Vitale depicts the Byzantine Emperor Justinian, who reconquered Italy in the 6th century and reunited the Eastern and Western Roman Empires for a short time. Ravenna was the Byzantine capital of the Western Region. Before that(around 400) Ravenna was actually the Roman capital under Emperor Honorius.
Basilica di San Vitale's more recent frescos
Battistero Neoniano
Basilica di Sant'Apollinare in Classe
It blows me away to think that these churches were built just 400 years after Jesus. It's an amazing time in history, the decline of the Roman Empire in Italy, the art and culture of the Byzantine Empire, and just a couple hundred years before Islam.