The construction of the Pantheon of King Duarte, most commonly known as the Imperfect or Unfinished Chapels, is said to have begun around 1434, during the first year of this king’s reign.
This construction, which was the responsibility of an architect called Huguet, masterfully represents his architectural capacity and know-how. It is made up of seven funerary chapels which were finished during the reign of King Manuel, and which bear on the vaults carved keys with coats-of-arms and emblems that identify their recipient.
Later, during the reign of King John III, a verandah of the renaissance style, dated 1533, was built over the portal of the Imperfect chapels with an Italian structure and decoration, attributed to Miguel de Arruda. In the forties of the twentieth Century, the double tomb of King Duarte and Queen Leonor was placed in the axial chapel.