Clothier's Seal, Cloth Seal, Serge, Image & Found by Derfel.
Found on Thames foreshore, 33mm.
Rivet disc of two disc cloth seal showing RB ligature with pellet annulus around containing inscription - SARGES.TAVИT(AV?)И // (head of rivet) S in ring of pellets, inscription around - ...ONROBE...
The inscription around the S suggest this clothier was another Robert whose surname ended in ON and, from the ligature, began with B.
See also seals 993, 1381 and 6732, p212, Provenanced Leaden Cloth Seals by Geoffrey Egan, Sub-Department of Medieval Archaeology, University College, University of London, submitted for the degree of Doctor of Philosophy, 1987, "These seals are unlikely to be earlier in date than the late 16th century."