A form of Maxen or Magnus-related names, associated with greatness; also known in Welsh tradition as Macsen.
Maxen is the ancient Welsh form of Maximus, and it carries with it one of the most remarkable stories in the overlap between Roman history and Celtic legend. Magnus Maximus was a Roman general of Spanish origin who served in Britain and declared himself Emperor of the Western Roman Empire in 383 AD. In Welsh legend and literature, he is remembered as Macsen Wledig — "Wledig" being an honorific for a great ruler — and his story forms the backbone of one of the tales in the Mabinogion, the great medieval collection of Welsh mythology.
In that tale, Macsen dreams of a beautiful woman in a distant land, embarks on a quest to find her, and ultimately wins both a wife and a kingdom through the courage of her brothers. The Welsh form Macsen (of which Maxen is a variant anglicization) thus carries a double prestige: the historical weight of Roman imperial ambition and the mythological grandeur of Celtic romance. Maximus itself descends from the Latin "maximus," meaning "greatest" — a superlative that Romans gave to generals who had won a decisive military victory.
It is the same root that gives us "maximum" and the papal name format (Pius Maximus, etc.) and the gladiator name Maximus immortalized in Ridley Scott's 2000 film. In contemporary naming, Maxen offers something Max and Maximus cannot quite match: a name that is both ancient and genuinely obscure, rooted in a specific and storied cultural tradition while remaining accessible and strong-sounding to modern ears. It is gaining quiet traction among parents drawn to Celtic and historical names with genuine provenance.