The Montefortino helmet appeared in Italy in the 4th century BCE, brought by Celtic groups such as the Senones, and soon became the dominant helmet type in the Roman Republic. Influenced by both Etruscan and Celtic designs, it offered a balance of protection and practicality, making it well suited for mass armies. By around 300 BCE, Roman soldiers had widely adopted it, and for centuries it remained the standard headgear of the legions. The helmet was easily recognized by its rounded or conical shape, crowned with a central knob that often served to hold a plume. Its rim was extended into a neck guard at the back, deflecting downward blows, while cheek pieces—often made of perishable material—were suspended from small rings on the sides. Many examples also show rope-like edging or a pinecone-like decoration on the knob, details that hint at Celtic craftsmanship. The curved bowl was designed to deflect sword strikes and projectiles, combining elegance with battlefield function. Early versions were more ornate, reflecting a time when Roman soldiers provided much of their own equipment and often invested in decoration. As the Roman army expanded during the late Republic, however, the helmets became plainer and more standardized, produced in large numbers to equip masses of poorer recruits. Inscriptions found on some helmets show that soldiers sometimes marked them with their names, giving them a personal identity amid the uniform ranks. The Montefortino remained in use well into the 1st century CE, gradually giving way to the Coolus type, which was simpler and better suited to large-scale production. Even then, the Montefortino did not disappear entirely; it lingered in use with elite units like the Praetorian Guard. Its long service life shows how adaptable the design was, bridging the transformation of Rome’s army from a citizen militia into a professional force. In Roman art, such as frescoes from Pompeii, soldiers are often depicted wearing the Montefortino, a reminder of its association with the Republican legions that conquered Italy and the wider Mediterranean. Today, surviving examples found across Italy, Spain, and Gaul highlight how widespread the helmet became, testifying to its central place in both Celtic and Roman military traditions.