Rhadmanthus, along with Minos and Aeacus, is one of the judges in the Underworld. Rhadamanthus and Rhadamanthine describe anyone who is rigidly just and strict.
In Greek myths, Rhadamanthus (also transliterated as Rhadamanthys or Rhadamanthos) was a wise king, the son of Zeus and Europa. Later accounts even make him out to be one of judges of the dead. His brothers were Minos and Sarpedon.