A significant monastery in the reflection of its documents - a foundational work on the history of monasteries and territories in Lower Saxony. Loccum is one of the most well-known and best-preserved monasteries in Lower Saxony. Founded around 1163 by the Counts of Hallermund, the Cistercian convent was able to acquire extensive land holdings until about 1330: a cohesive lordship developed in the area between Lake Steinhude and the Weser River, with further focal points lying north of the monastery into the County of Hoya, near Wunstorf and Rinteln, between Deister, Süntel, and the Leine lowlands, as well as around Oedelum. The well-preserved collection of documents, which reflects the significant expansion phase of the monastery, is the subject of this work. It provides reliable brief summaries and transcriptions of over 1600 documents from the late 12th century to the late.