and carpenters were especially valued across the region and even held monopolies in some Castilian cities such as Burgos. Other chapels were progressively created around the interior periphery of the building over the following centuries, many of them funerary chapels built through private patronage. The first precisely-dated chapel known to be built along the west wall is the Chapel of San Felipe and Santiago, in 1258. The Chapel of San Clemente was created in the southeast part of the mosque before 1262. A couple of early Christian features, such as an altar dedicated to San Blas (installed in 1252) and an altar of San Miguel (1255), disappeared in later centuries. The first major addition to the building under Christian patrons is the Royal Chapel (Capilla Real), located directly behind the west wall of the Villaviciosa Chapel. It was begun at an uncertain date. While it is sometimes believed to have been started by Alfonso X, Heather Ecker has argued that documentary evidence proves it wasn't begun before the 14th century when Contanza of Portugal, wife of Ferdinand IV, made an endowment for the chapel. It was finished in 1371 by Enrique II, who moved the remains of his father Alfonso XI and grandfather Ferdinand IV here. (Their remains were later moved in 1736 to the Church of San Hipólito.) The chapel was constructed in a lavish Mudéjar style with a ribbed dome very similar to the neighbouring dome of the Villaviciosa Chapel and with surfaces covered in carved stucco decoration typical of Nasrid architecture at the time. This prominent use of the Moorish-Mudéjar style for a royal funerary chapel (along with other examples like the Mudéjar Alcázar of Seville) is interpreted by modern scholars as a desire by the Christian kings to appropriate the prestige of Moorish architecture in the Iberian Peninsula, just as the Mosque of Cordoba was itself a powerful symbol of the former Umayyad Caliphate's political and cultural power which the Castilians were eager to appropriate. In the late 15th century a more significant modification was carried out to the Villaviciosa Chapel, where a new nave in Gothic style was created by clearing some of the mosque arches on the east side of the chapel and adding Gothic arches and vaulting. The nave is dated to 1489 and its construction was overseen by Bishop Íñigo Manrique. The nave originally had a series of Byzantine-Italian style frescoes by