The "druids," powerfully influential priests in pre-Christian Ireland, are mentioned fairly often in Ulysses. They resonate in popular imagination millennia after their decline, but since they left no written records little can be said with certainty about them. 

JH 2018

Two Druids, a 19th century engraving based on an illustration in Bernard de Montfaucon's Antiquitas explanatione et schematibus illustrata (1719 ), itself reproducing a bas-relief found at Autun, France. Source: Wikimedia Commons.

A fanciful impression of An Arch Druid in His Judicial Habit, illustration in The Costume of the Original Inhabitants of the British Isles, by S. R. Meyrick and C. H. Smith (1815). Source: Wikimedia Commons.