Caligae

Roman caligae were the heavy-soled, hobnailed military sandal-boots famously worn by legionary soldiers and auxiliaries throughout the Roman Republic and Empire. Their durable design allowed soldiers to march long distances in diverse climates without blistering or overheating. Dozens of iron nails were hammered through the sole. The iron hobnails drastically reduced wear and provided excellent traction on soft, slippery, or uneven ground.

The nails acted like cleats on rough, muddy, or sandy terrain and provided an offensive advantage in close-quarters combat. Roman soldiers were called caligati. ("booted ones") Emperor Caligula got his famous nickname "Little Boot" because his parents dressed him in miniature soldier's armor including caligae as a toddler. The distinctive clattering and crunching sound of thousands of hobnailed sandals marching in unison struck fear into Rome's enemies.

By the late 1st century, the Roman military began transitioning toward enclosed leather boots, known as calcei, which offered better protection in harsh and cold environments.