Cloth Seal, Cross on Shield, M, Image & Found by Peter Eggers.
Found in a farmyard in landfill from Amsterdam, Rokin, 24 x 19mm, 10.8g.
Cross on shield // medieval font M
Structure is similar to dyer's one part seals found along the Thames foreshore, see BSG.CS.01555, but the dimensions are larger for this one and the font suggests it is probably from an earlier period.
Memmingen in southern Germany could be a possibility but no demi-eagle evident.