The Concatedral de Santa María de la Redonda is in the heart of the old town of Logroño. It was built on a primitive Romanesque church which in 1435 became a collegiate church. The Concatedral dates from the 16th century but underwent numerous alterations in the 17th and 18th centuries, which give the exterior a purely baroque appearance. The oldest part of the church is the central section. It is a hall church with three naves of the same height separated by large columns and covered with star shaped vaulting and tiercerons. The construction of the church is that of a model which is very widespread in the north of Spain. It was declared a natural monument in 1931 and was elevated to the category of Concathedral in 1959 by Pope John XXIII.