The Santa Iglesia Catedral Metropolitana de Nuestra Señora de la Asunción is an unfinished Catholic temple located in the city of Valladolid, seat of the Archdiocese of Valladolid.

Conceived in the 16th century and designed by the architect Juan de Herrera, it is a Herrerian style building with Baroque additions.

It is 40-45% built, due to the lack of resources for a project of such magnitude and the expenses caused by the difficult foundations of the temple, located in an area with a great unevenness in the land.

It obtained the category of cathedral in 1595, after having been a collegiate temple dependent on the diocese of Palencia in its second stage as collegiate church.

It is located in the center of the city, in a slightly elevated area, near the church of Santa María La Antigua and built next to the collegiate church of Santa María, former collegiate church of Valladolid, some of whose spaces were destroyed to continue with the new works.

In the last quarter of the 11th century, King Alfonso VI entrusted Count Pedro Ansúrez with the repopulation and administration of this area that today comprises the province of Valladolid. The most important population centers, on the banks of the Pisuerga River, were Cabezón and Simancas, in whose jurisdictional lands agricultural villages were emerging.

One of these towns, Valladolid, was chosen by Count Ansúrez as his and his family's settlement and as the center from which he would organize and govern the entire repopulation of the environment.

At that time Valladolid was a village surrounded by a defensive fence, which had a fortress or castle and two churches dedicated to two traditional Hispanic saints: San Julián and San Pelayo.

Count Ansúrez chose the area outside the walls to build his own palace. In this way he began an expansion of the town towards the southeast.

In addition to the palace, according to tradition, he built a private church or chapel, which would be the origin of the current church of Santa María La Antigua, and a Collegiate or Main Church that came to inherit the prominence of the said church of San Pelayo and that enhanced the religious importance of the town.

This main church, built in Romanesque art, was called Santa María la Mayor and was the origin of the Valladolid cathedral.