Gaius Marius is said to have come from aristocracy

South of Latium in Italy, near the city of Aprinum, Gaius Marius was born in 157 BC. Shortly before his birth in 188 BC, the town was taken by the Romans in the late 4th century BC and first given Roman citizenship without the opportunity to vote. Plutarch reports that Marius' father was a laborer, but given that Marius had connections to Rome's nobility, stood for local office in Arpinum, and had several other notable accomplishments, it is probably certainly untrue. He was likely born into a prominent local family with equestrian rank, based on his marriage ties to the local nobility in Arpinum.

Even as a young man, Marius was not poor or even middle class; he was most definitely born into inherited wealth, most likely derived from holding substantial amounts of land. However, many of the difficulties he encountered during his early career in Rome demonstrate how difficult it was for a "new man" to be accepted into the upper classes of Roman society.

In reality, his family had more than enough money to sustain not just one member of the family in Roman politics, but two: Marius' younger brother, Marcus Marius, also became involved in politics in Rome.