The castle courtyard, a former patrician seat, still consists of the so-called Romanesque House (around 1200), the former manor house (1559) and the Daelen Gate (1551). The Romanesque House is the preserved part of an originally larger house. It is considered one of the oldest preserved secular residential buildings in Westphalia. The stately late Gothic/Renaissance manor house has remained almost unchanged on the outside, but has been remodeled several times on the inside in the course of its history. Above the part with a cellar, in the banqueting hall, the so-called Knights' Hall, interesting stucco reliefs from the time of construction have been preserved. They were added in 1939 by the sculptor Wilhelm Wulff.
The Daelen Gate takes its name from the former owners, the von Dael family. The town history museum, which is located in the courtyard, shows exhibitions on the history of the town and the church, copperplate engravings by Heinrich Aldegrever (1502 to ca. 1555), or the exhibition "Everyday life in the Middle Ages" on the different floors. In addition, the department of prehistory and early history presents, among other things, the famous "garnet disc brooch" from the early medieval burial ground at Lübecker Ring. Furthermore, the last abbess chair from the St. Walburgis monastery, finds from the Paradiese monastery and other precious objects are on display. Today, the Knights' Hall is also used for receptions of the city of Soest and as a wedding hall.
The Burghof-Museum Soest is a sight of WasserEisenLand - Industriekultur Südwestfalen.