The Romanesque church of Santa Maria de Retortillo has been located on the ruins of the Roman city of Julióbriga. It looks like it was built in the late XII. It has one nave and one apse. The main west door is hidden under the monumental staircase was later to reach the pockets of the belfry. In animals of the arcades there is a certain resemblance to those of Villacantid (Campoo of Suso), so it is possible that the whole church has been realized in the late twelfth. There were doubts to see some difference in style, but the struggles of knights, the Triumphal Arch, lead us to the great masters working in Aguilar de Campo. Beside the church, there is a high medieval necropolis of slabs, stones and sarcophagi that could go to the eighth centuries X. In this church with the necropolis is the stele with the name Teudesinde preserved in the Museo Regional de Santander . Apparently, once Julióbriga city was uninhabited centuries had to pass until people settled back in place.