In 1186 monks from the
Cistercian abbey of Loccum founded the
monastery of Reynevelde near where the stream Heilsau meets the river
Trave. The monks created about 60 ponds to raise fish to eat on the days meat was not allowed. The Abbey prospered until the Reformation.
Johan of Plön is said to have been buried in the abbey in 1359 among other "nobles". In 1582 it was closed down by the dukes of
Plön and most of the buildings except for the church demolished. A four winged castle was built 1599–1604 from the material. When the Plön line of the Dukes died out in 1761 the duchy of Plön including Reinfeld and the castle fell to King
Frederick V of Denmark. The castle was considered useless and was demolished in 1775, the old bricks being reused for a new yet smaller building. In 1635 the dam of the Herrenteich broke and the water damaged the old abbey church so it had to be taken down. A new Church was built the following year on a nearby hill called "Eichberg" (Oak hill). The Danes ruled in Reinfeld from 1762 until 1864. After a short period under Austrian rule as a result of the
Second War of Schleswig,
Holstein became a province of
Prussia in 1866. Reinfeld became officially a town in 1926. ==Coat of arms==