The cathedral has a heptogonal sanctuary, with two rows, and tierceron vaults; it was built at the beginning of the 15th century to serve as a burial chamber for Archbishop Sancho de Rojas.
Kapela svetega Evgena (imenovana tudi svetega Petra starejšega ali "Corpus Christi"), ki se nahaja na južni strani, ohranja arhitekturni slog 13. stoletja, v nasprotju s preostalim delom katedrale.