Armin vs Arminius

Armin and Arminius both are nouns.

Word	Noun	Adjective	Verb	Adverb
Armin	Yes	No	No	No
Arminius	Yes	No	No	No

As nouns, Armin and Arminius are synonyms defined as:

Armin and Arminius: German hero; leader at the battle of Teutoburger Wald in AD 9 (circa 18 BC - AD 19)

Other synonyms of Armin include Hermann.

Armin (noun)	Arminius (noun)
German hero; leader at the battle of Teutoburger Wald in AD 9 (circa 18 BC - AD 19)	German hero; leader at the battle of Teutoburger Wald in AD 9 (circa 18 BC - AD 19)
	Dutch Protestant theologian who founded Arminianism which opposed the absolute predestinarianism of John Calvin (1560-1609)