Watch List notes:

William I (1066-87), Penny, Sword type, Derby, Swartbrand, 1.23g, 12h, rev. + spartbrand on d, the last three letters ligate, the as unbarred (EMC 2019.0131 this coin; BNJ [1907], pp. 54 ~ 'conjecturally attributed to Wallingford'~; N.846; BMC VI; S.1255), slight die flaws, otherwise good very fine, an extremely rare type, the moneyer only known for this issue for the Conqueror's coinage.

Estimate: £1,500 - £2,000