Electorate of Cologne
The municipality's oldest known seal, from the late 14th century, already bears these charges, and both refer to the former landholder, the Electorate of Cologne, whose arms are seen on the sinister (armsbearer's left, viewer's right) side. The keys on the dexter (armsbearer's right, viewer's left) side refer to Saint Peter, who was Cologne's patron saint.