The ancient Frisii enter recorded history in the Roman account of Drusus's 12 BC war against the Rhine Germans and the Chauci. They occasionally appear in the accounts of Roman wars against the Germanic tribes of the region, up to and including the Revolt of the Batavi around 70 AD. Frisian mercenaries were hired to assist the Roman invasion of Britain in the capacity of cavalry. They are not mentioned again until 296, when they were deported into Roman territory as "laeti" (i.e., Roman-era serfs; see Binchester Roman Fort and Cuneus Frisionum). The discovery of a type of earthenware unique to 4th century Frisia, called "terp Tritzum", shows that an unknown number of them were resettled in Flanders and Kent, probably as "laeti" under Roman coercion.