From Latin Marius, likely connected to Mars, the Roman god of war. The name belonged to one of Rome's greatest military commanders, Gaius Marius, making it a name with real martial history behind it.
Marius
warlike, of Mars
Mark
Mark derives from the Latin 'Marcus,' which is thought to be related to Mars, the Roman god of war, suggesting meanings of 'of Mars' or 'warlike.' It may also carry the sense of 'hammer' from a pre-Latin root.