Eric IV of Denmark, also known as Eric Ploughpenny, was the monarch of Denmark who reigned from 1241 until 1250. Born in Copenhagen around 1216 to Valdemar II, he had previously served as the Duke of Schleswig starting in 1218. His rule was marked by significant tension with his brother, Abel of Schleswig, and his controversial decision to levy taxes on those owning ploughs. This fiscal policy earned him his distinctive nickname before his life ended prematurely in Schlei.