Baron Conrad Mardefelt, formally Conrad von Maesberg, friherre Marderfelt (c. 1610–1688) was a field marshal of Sweden. He was a nobleman of Pomeranian origin.
After having distinguished himself as a fortification officer with Lennart Torstensson, he was entrusted with the command of all the Swedish fortifications on German soil in 1646. He became a general in 1673 and a field marshal in 1675.
King Charles XI created him a freiherr in 1677 with the baronial name Marderfelt (from which some literature has tended to drop one "r").
He was the father of Arvid Axel Mardefelt.[1]