Karl von Zois was born in Ljubljana and baptized Carolus Philippus Eugenius Zoiss.[4] The Zois family was of Lombard origin; Karl's father was Michelangelo Zois (1694–1777), a merchant who married a Carniolan noblewoman, and was nobilitated in 1739. The family was based in Ljubljana (German: Laibach). His brother was the natural scientist and patron of the arts Sigmund Zois.