Coat of arms of the Duchy of Czersk

Coat of arms of the Duchy of Czersk is a legendary creature in folklore of Masovia in Poland, that is depicted as a Slavic dragon or wyvern.

It most likely was introduced as a coat of arms of the Czersk Land thanks to Magnus, son of Harold Godwinson, king of England, that was a komes in Masovia in the 12th century.

According to Jan Długosz, Piast Dragon had appeared on the banner used by duke Janusz I of Warsaw during the Battle of Grunwald in 1410.

[6] Currently, the dragon is present in the coat of arms of several counties of Masovian Voivodeship, Poland, that are: Garwolin (since 2002),[7] Grójec (since 2000),[8] Ostrów (since 2002),[9] Otwock,[10] Pruszków, and Warsaw West.

According to the local Masovian folklore, the dragon lived in the dungeons located underground between the Czersk Castle and the village of Coniew, and guarded the treasures of duke Konrad I of Masovia.