State : Nordrhein-Westfalen
District (Kreis) : Ennepe-Ruhr-Kreis
Additions : 1939 Ende
The arms were granted on June 13, 1902.
Herdecke received town rights in 1355 from Count Engelbert III of the Mark, but the town did not develop into a proper city. In 1739 King Friedrich Wilhelm I of Prussia granted the city rights. The oldest seal is known from 1770, but is probbaly some decades older. It shows an oak tree, the so-called Hertha Eiche (oak of Hertha). This tree played a role in the legendary founding of the local convent in the early Middle Ages. The tree first appears in a shield in the late 19th century. The colours were derived from the colours of the Counts of the Mark.
Literature : Stadler, K. : Deutsche Wappen - Bundesrepublik Deutschland. Angelsachsen Verlag, 1964-1971, 8 volumes.