Westwerk, i.e. west work, is also known as the western body. It spread between the end of the 9th century and the 10th century in Carolingian churches. Formed by a central structure flanked by two towers, it took on a fortified appearance on the outside, while on the inside it was a space of considerable importance. It was also politically important, since the emperor attended church functions from the loggia, usually located on the second floor.