An ancestor of Palamedes in the Italian I Due Tristani. A pagan king who secretly became a Christian, he was overthrown and imprisoned, but was kept alive in prison through the miracle of God.
His character, as well as his name, seems to be a combination of Evalach (Evelake) in the Vulgate Estoire del Saint Graal and Esclabor, Palamedes’ father.
Source
I Due Tristani | 1555