Agneta Willeken (c. 1497-1562) was the lover of the German mercenary Marcus Meyer, one of the most notable participators of the Count's Feud.
She stayed in Hamburg and became the lover of Marcus Meyer, with whom she corresponded when he left to Lübeck and married a wealthy widow.
During Meyer's siege of Varberg Fortress in 1535, she sent him a letter, which was taken by the King of Denmark and used as propaganda material.
This letter was used to point out Willeken as a major instigator and political participator of the war.
She was pointed out as the main force behind the decision of the Lübeck mayor, Jürgen Wullenwever, to declare war on Holstein.