Radagaisus (died 23 August 406) was a Gothic king who led an invasion of Roman Italy in late 405 and the first half of 406. A committed Pagan, Radagaisus evidently planned to sacrifice the Senators of the Christian Roman Empire to the gods, and to burn Rome to the ground. Radagaisus was executed after being defeated by the half-Vandal general Stilicho. 12,000 of his higher-status fighters were drafted into the Roman army and some of the remaining followers were dispersed, while so many of the others were sold into slavery that the slave market briefly collapsed. These Goths later joined Alaric I in his conquest of Rome in 410.
Radagaisus's force probably consisted of about 20,000 fighting men. Many of the fighters were accompanied by their families and other noncombatants, meaning that the total size of Radagaisus's group may have approached 100,000.
Radagaisus, whose early career and ultimate origins are unknown, fleeing Hunnic pressures, invaded Italy without passing through the Balkans, which indicates that his invasion began somewhere on the Great Hungarian Plain, west of the Carpathian Mountains.Archaeological finds of coin hoards, buried by residents who were apparently aware of Radagaisus's approach, suggest that his route passed through southeastern Noricum and western Pannonia. About this time Flavia Solva was burned out and largely abandoned and Aguntum was devastated by fire. An indeterminate number of refugees fled ahead of his army as it marched over the Alps. It was said by contemporaries that Arian Christians swelled his forces.