The most outstanding element of the interior is undoubtedly the golden Retablo Mayor (main altarpiece) in the Cathedral’s main chapel. This magnificent masterpiece was crafted by the Flemish artisan Pierre Dancart, who dedicated forty-four years working on the reliefs, starting in 1482. It wasn’t until 1564 with the additional help from other artists that the altarpiece was finally completed. To separate onlookers from the altarpiece, large iron grilles, forged between 1518 and 1532, were installed.

The Retablo Mayor, the world’s largest altarpiece consists of thirty-six gilded relief panels depicting scenes from the Old Testament and the lives of saints. In front of the wall of gold sits a statue of Santa Maria de la Sede, the patron saint of the cathedral.