Yclept (also ycleped) is the archaic past participle of "clepe," meaning "named" or "called." The "y-" prefix marks past participles in Middle English, derived from Old English "ge-."
Chaucer uses yclept regularly: "a knight ther was, and that a worthy man, yclept Sir Thopas." Students should recognize yclept as specifically medieval—even by Shakespeare's time it was deliberately archaic.
Spenser employs yclept for medievalizing effect in The Faerie Queene. The construction typically follows "he was yclept [name]" or "by name yclept [name]." Understanding the y- prefix helps recognize other archaic past participles (ywis = known certainly, ywrought = wrought). Modern readers encounter yclept almost exclusively in Chaucer and
conscious medieval
imitation. The term completely disappeared from living language by 1600. In modern fantasy literature, yclept occasionally appears for pseudo-medieval atmosphere. Compare "called" (modern), "named" (modern), "cleped" (archaic present), and "yclept" (archaic past participle).