Byzantium vs Byzantine

Byzantium and Byzantine both are nouns.

Word	Noun	Adjective	Verb	Adverb
Byzantium	Yes	No	No	No
Byzantine	Yes	Yes	No	No

Byzantium (noun)	Byzantine (noun)
an ancient city on the Bosporus founded by the Greeks; site of modern Istanbul; in 330 Constantine I rebuilt the city and called it Constantinople and made it his capital	a native or inhabitant of Byzantium or of the Byzantine Empire
a continuation of the Roman Empire in the Middle East after its division in 395

Byzantium (adjective)	Byzantine (adjective)
	of or relating to or characteristic of the Byzantine Empire or the ancient city of Byzantium
	of or relating to the Eastern Orthodox Church or the rites performed in it
	highly complex or intricate and occasionally devious