- Basilica of San Vitale
The construction started in 526 on the orders of Bishop Ecclesius of Ravenna. Bishop Maximian completed the construction in 547. The building is octagonal, with the entrances next to the altar. So... strange. - The Arian Baptistery
The baptistery was built around 500 under the reign of the Ostrogothic king Theoderic. Arian Christianity was different from the Orthodox Christianity as they considered Christ as not truly divine but rather a created being. - The Arian Baptistery
Ha, 1500-year old topological defects :-D - The Orthodox Baptistery
The Orthodox baptistery, also called the Neonian Baptistery. Built by bishop Ursus but decorated by bishop Neon in 470.