Alonso Martinez depicting saints and kings, but only one of these frescoes has been preserved to the present day and is being kept at the Museum of Fine Arts in Cordoba. Major alterations (16th–18th centuries) The most significant alteration of all, however, was the building of a Renaissance cathedral nave and transept – forming a new Capilla Mayor – in the middle of the expansive mosque structure, starting in 1523. The project, initiated by Bishop Alonso de Manrique, was vigorously opposed by the city council of Cordoba. The cathedral chapter eventually won its case by petitioning Charles V, king of Castile and Aragon, who gave his permission for the project to proceed. When Charles V later saw the result of the construction he is reputed to have been displeased, however, and is claimed to have commented: "You have built what you or anyone else might have built anywhere; to do so you have destroyed something that was unique in the world." The architect Hernan Ruiz I was put in charge of the design of the new nave and transept. Before his death in 1547 he built the choir walls up to the windows and the gothic vaults on the south side. He also worked on the mosque building's eastern section (the extension added by Al-Mansur) by adding gothic vaulting to the mosque naves in this area. His son, Hernan Ruiz II "the Younger", took over the project after his death. He was responsible for building the transept walls to their full height as well as the buttresses upholding the structure. After him, the project was entrusted to architect Juan de Ochoa, who completed the project in a Mannerist style. The final element was the construction of the elliptical central dome of the transept, built between 1599 and 1607.In 1589 a strong storm (or earthquake) caused damage to the former minaret, which was being used as a bell tower, and it was decided to remodel and reinforce the tower. A design by Hernán Ruiz III (son of Hernán Ruiz II) was chosen, encasing the original minaret structure into a new Renaissance-style bell tower. Some of the upper sections of the minaret were demolished in the process. Construction began in 1593 but eventually stalled due to resources being spent instead on the construction of the new cathedral nave and transept happening at the same time. Hernán Ruiz III died in 1606 and