“...By the late Byzantine period (ca. 550 AD)...”
EXCUSE ME!
Byzantium: Roman Emperor Diocletian splits imperial administration between east and west, 285 AD - Constantinople falls to the Ottoman Turks, 1453 AD.
Ironically, it’s a little late to bring that up. ;’)
It’s “Late Byzantine” for that area, since the area was overrun by the Arabs in the 630s.