The name Marius is a boy's name of Latin origin. Marius and is often added to lists like Cool Boy Names From Ancient Cultures and discussed in our forums with posts like "A brother or sister for little Jack or Olivia".
From the experts:
Marius, frequently heard in Germany and France, is a slightly fusty yet accessible name that has (Les Mis) to Anne Rice. With the rise in interest in such Latin names as Maximus and Atticus, Marius might start attracting more attention. Mario, the Italian, Spanish and Portuguese version of Marius, is much more widely used.