The beginning of the i 2th century was the age of the atabegs (regents or stadtholders).
These dynasties were founded by emancipated mamelukes, who had held high office at court and in camp under powerful amirs, and who, on their death, first became stadtholders for their descendants, and then usurped the throne of their masters.
The younger line became stadtholders of the other states after the extinction of the elder, and were the ancestors of the present royal family of the Netherlands.
Though the stadtholders of the house of Orange-Nassau were of princely rank and intermarried with the royal families of Europe, they were not sovereign princes.
It was restored in 1816 and contains a portrait gallery of the Frisian stadtholders.