Andreus is a learned variant of Andrew, from Greek roots meaning manly or brave.
Andreus stands at the root of one of Western civilization's most widespread names. In Greek mythology, Andreus was a primordial figure — son of the river god Peneus according to some sources, and considered the legendary first king and eponymous founder of Orchomenos in Boeotia, one of the oldest cities of ancient Greece. He is among the earliest named mortals in the mythological genealogies, a founding ancestor through whom later Greeks traced the origin of their cities and peoples.
The name derives from the ancient Greek *anēr* (ἀνήρ), genitive *andros*, meaning "man" — making Andreus essentially "the manly one" or "he who embodies humanity." This root gave rise to the entire *Andreas* family of names — Andrew in English, André in French, Andreas in German and Scandinavian, Andrei in Slavic languages, and Aindréas in Irish. Saint Andrew the Apostle, one of the twelve disciples and patron saint of Scotland, Russia, and Greece, spread this root across Christendom with remarkable thoroughness.
The apostle's name became so embedded in European naming culture that Andrew and its variants have ranked among the most common male names in the West for over a millennium. Andreus itself, as a distinct form, is rare and classical — it reads as a name pulled directly from an ancient text. For parents drawn to Greek mythology and classical antiquity, it offers the gravitas of a founding figure without the ubiquity of its descendants. It is a name for those who want their child to carry not just a name but an origin story — the very root from which a thousand other names grew.