After years of alarming Roman defeats against migrating Germanic and Celtic tribes, Marius reorganized the legions and lured the Teutones into a disadvantageous battle. The victory, followed a year later by the destruction of the Cimbri, saved Rome from what contemporaries feared was an existential invasion and cemented Marius's reputation as a military reformer.
For years the Cimbri and Teutones had rampaged through Roman territory, inflicting humiliating defeats that terrified Italy with memories of the Gallic sack of Rome centuries earlier. Marius, elected consul repeatedly to deal with the crisis, drilled his legions relentlessly and introduced tactical innovations, including a redesigned javelin pilum meant to bend on impact and foul enemy shields.
At Aquae Sextiae, Marius positioned his forces on high ground and baited the Teutones into an exhausting uphill assault, then unleashed a hidden reserve force on their flank and rear. The slaughter was so complete that ancient sources claim local Gauls used Teutone bones to fence their vineyards for a generation. The victory helped make Marius one of the most powerful men in Rome and foreshadowed the military strongmen who would eventually topple the Republic.