In 1180–4, in place of the old, square-ended, eastern chapel, the present Trinity Chapel was constructed, a broad extension with an ambulatory, designed to house the shrine of St Thomas Becket. A further chapel, circular in plan, was added beyond that, which housed further relics of Becket, widely believed to have included the top of his skull, struck off in the course of his assassination. This latter chapel became known as the "Corona" or "Becket's Crown". These new parts east of the quire transepts were raised on a higher crypt than Ernulf's quire, necessitating flights of steps between the two levels. Work on the chapel was completed in 1184, but Becket's remains were not moved from his tomb in the crypt until 1220. Further significant interments in the Trinity Chapel included those of Edward Plantagenet (The "Black Prince") and King Henry IV.