Rietberg was first mentioned as 'Rietbike' around the year 1100. This name refers to Ried which is an old name for reed and to 'Bach' which means creek. There was a castle that dated back to the 11th century. From 1237, it was seat of the imperial
County of Rietberg. The County of Rietberg was an independent German territory until the year 1807. In the
Middle Ages the Rietberg county was a very small state. Nevertheless, Rietberg had its own militia, its own currency and its own laws. Even foreign policy, on a small scale, was conducted independently. Until the 17th century Rietberg coined its own money. Until the 18th century the government was located in the castle, built in the 14th century.
Wenzel Anton, Prince of Kaunitz-Rietberg, the Austrian chancellor, inherited the county from his mother. At the beginning of the 19th century the castle was torn down because it was not needed anymore. Only the
St. John's chapel from 1748 can still be visited today. In the year 1807 Rietberg became a part of
Kingdom of Westphalia, while the title
Count Rietberg remains extant in the
House of Liechtenstein, with
Hans-Adam II, Prince of Liechtenstein and each born member of his dynasty and their
dynastic wives bearing the title currently. The village itself was not independent anymore, in the year 1843 the municipality Rietberg was established. Since 1970 Rietberg has been organised politically as it is today. ==Mayors==