Where does “Markuss” come from?

Markuss (Latvian) comes from Latin Mārcus, from Latin Martīnus, from Latin -īnus, from Proto-Italic -īnos, from Proto-Indo-European -iHnos, from Proto-Indo-European -no- — adjectival suffix.

Ancestry of “Markuss”, step by step

Step	Language	Word	Meaning
1	Latin	Mārcus	—
2	Latin	Martīnus	—
3	Latin	-īnus	of or pertaining to; -ine
4	Proto-Italic	-īnos	of/belonging to
5	Proto-Indo-European	-iHnos	Creates adjectives of materials
6	Proto-Indo-European	-no-	adjectival suffix

Every word from Proto-Indo-European -no- →Every word from Latin -īnus →Every word from Latin Martīnus →