Lailoken is a semi-legendary figure from 6th-century Britain, known as a madman and prophet in the Caledonian Forest. The name likely originates from the medieval Latin Laloecen, which may be related to the Welsh llallo meaning "brother, friend". It appears in the Life of Saint Kentigern, where a fool called Laleocen correctly prophesies the death of King Rhydderch Hael. Lailoken is often identified with Myrddin Wyllt, the Welsh figure who inspired the Arthurian wizard Merlin. In Welsh tradition, Myrddin became a wild man after the Battle of Arfderydd, living in the forest and uttering prophecies. This parallel is reinforced by the Red Book of Hergest, where Myrddin is addressed as llallogan by his sister Gwenddydd, a term similar to Lailoken. The name has a variant form, Laloecen, in Brythonic. Its usage is historical, primarily appearing in early medieval texts from Scotland and northern England. The legend of Lailoken survives in manuscripts such as the late 15th-century Vita Merlini Silvestris. Meaning: "brother, friend" (possibly) Origin: Welsh/Brythonic Type: legendary/wild man Usage regions: Historic Scotland and northern England