Rose window

Items made by Master Mateo in the cathedral collections include significant pieces from the great western facade that completed the Portico of Glory. This facade was first modified in the 16th century to hold doors that would close the cathedral. It was later replaced with the current baroque facade, which made use of the previous structure and covered it with new stone adornments.

In "Report on the Works in the Cathedral of Santiago" by churchwarden Canon José de Vega y Verdugo, there is a drawing of the western facade as it was in 1656–57. The drawing features the large rose window, or "great mirror," the main purpose of which was to flood the cathedral's central nave with light, performing both a functional and symbolic role.

Several fragments of the rose window have been recovered, allowing a hypothetical reconstruction to be produced.

The piece has complex inner tracery with a central circular core featuring a star shape. Around the core are circular elements, each containing a star and linked by interlaced ribbons in relief. Around 1510, the rose window had colorful stained glass put in and, in early 1738, due to its poor condition, the chapter ordered that "materials be prepared for works on the mirror and tower, which looks onto the Plaza del Hospital, given the ruinous state of the mirror." Demolition started and the new Obradoiro Facade by architect Fernando de Casas y Novoa was begun.