Cloth Seal, French, Ypres, Castle, Image & Found by Adam & Lisa.
Found in Lincs. 15mm diameter.
One disc of a cloth seal with undeciphered marks on one side (possibly a castle gateway / portcullis) and the impression of a woven cloth on the reverse. Some further markings on the head of the rivet (all that remains of the other disc) but again undecipherable.
See No.170, Fig.27, Egan, G., Cloth Seals, p.43-86 in Salisbury & South Wiltshire Museum Medieval Catalogue, Part 3, ed. Peter Saunders, 2001, "Probably a Continental civic or corporate seal, this could perhaps be an Ypres issue..."