Where does “Алексий” come from?

Алексий (Old East Slavic) comes from Ancient Greek Ἀλέξιος, from Ancient Greek -ῐος, from Proto-Indo-European -yós — Creates adjectives from noun or verb stems.

Ancestry of “Алексий”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	Ἀλέξιος	helper, defender
2	Ancient Greek	-ῐος	belonging to; of”, “belonging to”, “pertaining to
3	Proto-Indo-European	-yós	Creates adjectives from noun or verb stems

Words derived from “Алексий”

Аляксей

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