At the Battle of Adrianople in Thrace (modern Edirne, Turkey), the migratory Visigoths destroyed a Roman army led by Emperor Valens. The Roman heavy infantry, exhausted by marching in oppressive summer heat while wearing heavy iron mail and helmets, were outmaneuvered and crushed by the flexible, rapid charges of Gothic cavalry. This catastrophic failure demonstrated that heavy infantry armor without tactical mobility was a liability against shock cavalry.

This shocking military disaster sent shockwaves through the literate world, described as the end of an era by historian Ammianus Marcellinus. It inspired somber Latin elegiac poetry and Germanic oral lays that lamented the fall of Rome's iron wall and celebrated the ascendance of the horseman.