Posidonius was a Greek politician, astronomer, astrologer, geographer, historian, mathematician, and teacher native to Apamea, Syria. He was considered the most learned man of his time and, possibly,
Bust of Posidonius from the Naples National Archaeological Museum
Posidonius, depicted as a medieval scholar in the Nuremberg Chronicle
A druid was a member of the learned class of the ancient Celtic peoples of Gaul and Britain, described by Greek and Roman writers as a priest, teacher, judge and custodian of religious and legal tradi
Posidonius
…Celts, such as a story that in the past, men were paid to allow their throats to be slit for public amusement. But he noted that the Celts honored the Druids, whom Posidonius saw as philosophers, and concluded that, even among the barbaric, "pride and passion give way to wisdom, and Ares stands in awe of the…
Julius Caesar, whose Commentarii de Bello Gallico is the earliest detailed account of the druids.
Roman troops attacking the druids on Anglesey, as described by Tacitus. A 19th-century imagining of the scene.
'An Arch Druid in His Judicial Habit', an imaginative illustration from S. R. Meyrick and C. H. Smith, The Costume of the Original Inhabitants of the British Islands (1815). The gold collar copies a Bronze Age Irish gorget.
The oak and mistletoe ritual depicted by Henri-Paul Motte (1900)