| 157 BC | Born near Arpinum. |
| 133 | Serves with distinction at the final capitulation of Numantia, in Spain. |
| 128 | Probable service in Asia as elected military tribune. |
| c.123 | Quaestor. |
| 119 | Tribune of the people. Attacks the consul, Lucius Caecilius Metellus, a member of the family whose protegé he was, for opposing his bill to lessen the opportunities of intimidation at voting in the comitia tributa. |
| 115 | Elected praetor. Acquitted on a technicality of cheating at the polls. |
| 114 | Governor of Further Spain. |
| c.112 | Marries Julia, aunt of Julius Caesar. |
| 109 | Chosen as senior legate by Metellus Numidicus to fight against Jugurtha. |
| 108 | Elected consul. |
| 107 | Begins to reorganize recruitment to the army. Voted by comitia tributa to take over Metellus’s command. |
| 106 | End of wars against Jugurtha. |
| 104 | Second consulship. |
| 103 | Third consulship. Saturninus is tribune of the people. |
| 102 | Fourth consulship. Teutones destroyed. |
| 101 | Fifth consulship. Cimbri crushed. |
| 100 | Sixth consulship. Saturninus again tribune, but his violent tactics lead to his death. |
| 99 | Marius leaves for the east, where at a meeting with Mithridates VI, king of Pontus, he advises the king either to become stronger than Rome, or submit to Rome’s authority. |
| c.97 | Returns to Rome and builds himself a house near the forum. |
| 91-88 | Social War between Rome and Italian allies. |
| 88 | First consulship of Sulla, to whom is assigned the command against Mithridates. Sulpicius Rufus, tribune of the people, passes a law transferring the command to Marius. He is killed, and Marius and his adopted son take flight. |
| 87 | First consulship of Cinna, who is driven out by his consular colleague, but returns and with Marius captures Rome. Massacres in Rome. |
| 86 | Seventh consulship of Marius and second of Cinna. Death of Marius 13 January. |