Where does “Արկադի” come from?

Արկադի (Armenian) comes from Russian Арка́дий, from Ancient Greek Ἀρκάδιος, from Ancient Greek -ῐος, from Proto-Indo-European -yós — Creates adjectives from noun or verb stems.

Ancestry of “Արկադի”, step by step

Step	Language	Word	Meaning
1	Russian	Арка́дий	—
2	Ancient Greek	Ἀρκάδιος	Arcadius, a name borne by an Emperor
3	Ancient Greek	-ῐος	belonging to; of”, “belonging to”, “pertaining to
4	Proto-Indo-European	-yós	Creates adjectives from noun or verb stems

Every word from Proto-Indo-European -yós →Every word from Ancient Greek -ῐος →Every word from Ancient Greek Ἀρκάδιος →