Köln: Maria ad Gradus
Ca 1060 the chapter church Maria ad Gradus (Mariengraden; Maria im Kapitol) at Köln was built east of the Dom. It served as such up till 1802; then the chapter was disbanded. The church is demolished now.
A. Wolff: Der Kölner Dom
D-KNd 226, Graduale-Antiphonarium, prepared between 1353-1358.