The Domschatz Essen is the Museum of the Treasury of the Essen Cathedral. It is one of the most significant collections of religious works of art in Germany, almost unique in its completeness, given that only a few pieces have been lost over time. We are able to know its completeness thanks to the presence of the liber ordinarius, in which the liturgical use of objects is described.

The Essen Cathedral Treasury contains several artistically significant works, particularly from the Ottonian period, such as four processional crosses from the Ottonian era; a golden crown, said to be the childhood crown of Otto III, but is generally dated to the 11th century. It is, in any case, the oldest surviving crown of lilies; the sword of Saints Cosmas and Damian, a ceremonial sword covered with gold of the abbesses since Ottonian times; the Gospels of Theophane, an 11th century manuscript with a gilded cover and ivory plate carved in the center, the reliquary of the Holy Nail, donated by Theophane; he Golden Madonna, the oldest sculpture of Mary in Western art (kept in the cathedral), a two-meter high seven-branched candelabrum from the Ottonian era (kept in the cathedral). In addition to the Ottonian works, there are also valuable objects from later periods, such as the reliquary bust of San Marsus and sixteen Burgundian fibulae of the fourteenth century. Several manuscripts also belong to the collection, including the Great Carolingian Gospels of high linguistic and artistic significance, the Liber Ordinarius of Essen and the Liber of Essen. Finally, there is a showcase with objects on loan from the Diocesan Museum, such as the crosier, the mitres, the pectoral crosses and the rings of the deceased bishops of Essen.