 He landed on the neighboring island of Koön on 6 July and began besieging the town.Marstrand was defended by the fortress of Carlsten and the three strong-points Malepert (on the east side of the northern harbour inlet), Gustafsborg (by the southern harbour inlet), and Hedvigsholm (on a skerry located in the harbour itself).The defenders tallied 600, led by commander ("kommendant") Anders Sinclair.