San Lorenzo was one of the twelve religious buildings commissioned by king Ferdinand III of Castile in the city after its conquest in the early 13th century.
The church occupies the site of a pre-existing Islamic mosque, which in turn had been built above a Visigothic church. It was built between around 1244 and 1300, in a transitional style between Romanesque and Gothic architecture. It has the typical structure of Andalusian churches of the period, featuring a rectangular plan with a nave and two aisles, without transept and an apse.
It has a portico with three slightly ogival arcades, added in the 16th century. The Islamic minaret was converted into a Renaissance bell tower by Hernán Ruiz the Younger. Above the portico is the large Gothic-Mudéjar rose window. The nave has a coffered ceiling in Mudéjar-Renaissance style. The apse has 14th century paintings inspired by the Italian Gothic school, depicting Scenes of the Life of Jesus. There are also figures of saints and prophets with gilt halos, and a decoration imitating Byzantine azulejos. the high altar (17th century) has scenes of the life of St. Lawrence.
References:Sigmaringen Castle was first mentioned in the year 1077 in the chronicles of Petershausen monastery. The oldest parts of the castle are concealed beneath the alterations made during the 17th and the 19th centuries. The secret of the earliest settlement built on this defendable rock will never be fully revealed: large-scale excavation work would be necessary, which the extensive land development renders impossible. Judging from the many Roman remains unearthed in the area around Sigmaringen, the 12th century keep known as the 'Roman Tower' could be traced back to a Roman predecessor.
The castle remains that have been preserved (gate, great hall and keep) date back to the Staufer period around 1200. The castle remains were integrated into subsequent buildings. The foundations of the castle buildings are to a large extent identical to the surrounding castle wall.
These remains give us a good idea of how the castle might have looked during the 12th century.