"As Capelas Imperfeitas" ("The Unfinished Chapels") are a reminder that the monastery was never actually finished. They form a separate octagonal structure tacked on the choir of the church (via a retrochoir) and only accessible from the outside. It was commissioned in 1437 by King Edward of Portugal ("Dom Duarte", d.1438) as a second royal mausoleum for himself and his descendants. But he and his queen Eleanor of Aragon are the only ones buried here. (Eleanor died in exile in Toledo in 1445; her remains were moved here in 1456.)