Very little is known about the ancient druids. They left no written accounts of themselves, and the
The earliest known reference to the druids dates to 200 BCE, although the oldest actual description comes from the Roman military general Julius Caesar in his Commentarii de Bello Gallico (50s BCE). Later Greco-Roman writers also described the druids, including Cicero, Tacitus and Pliny the Elder. Following the Roman invasion of Gaul, druidism was suppressed by the Roman government under the 1st century CE emperors Tiberius and Claudius, and it had disappeared from the written record by the 2nd century.