At the end of the 19th and beginning of the 20th centuries, church building was largely rooted in historicism. At the same time, a trend emerged in Europe that is known today as the "liturgical movement". Benedictine monks, intellectuals and students sought the true roots of Christianity and in particular the authentic Catholic Mass. The philosopher and theologian Romano Guardini came to play a major role in this movement. Similar developments manifested themselves at the same time in Protestantism. This search for the true belief also exerted an influence on church construction. In this respect, Otto Bartning was a significant figure in Protestant ecclesiastical building, while in Catholicism, architects such as Dominikus Böhm, Martin Weber and Rudolf Schwarz played a major role. Based on new liturgical concepts, they proposed changes in the spatial organization of churches and advocated the use of new building materials. In 1922, for example, Auguste and Gustave Perret used exposed concrete and glass for the Notre Dame de la Consolation church in Le Raincy, while still exploiting Gothic forms. In his St Anthony's Church in Basle (1927), Karl Moser created the first major exposed-concrete church in the German-speaking world. Here, the column-free interior helps to concentrate attention on the altar. A prime example of a unified liturgical space in Germany is St Corpus Christi in Aachen (1930) by Rudolf Schwarz, where the use of reinforced concrete allowed the creation of thin membrane-like outer walls. Schwarz sought to draw up a typology of church building, defining a number of basic models: "holy inwardness", a closed, circular form (the ring); a "holy act of setting out", a three-quarter circle or T-shaped layout about the centre of the space; and a "holy quest", which manifested itself as a path (ill. 1).
