The Seamers were an old Scarborough family; and it seems likely that William was either the son or a close kinsman of the Adam Seamer who was twice town bailiff in the 1340s, and the owner of property and shipping there. He himself first comes to notice as early as November 1356, when he joined with other leading burgesses in witnessing a new ‘composition’ intended to settle factional disputes in the borough. He subsequently attested a number of local deeds, and also built up his own property holdings, acquiring land on the cliffs and near the Butter Cross. He married at some point before 1373, when he and his wife released their title to a messuage in Scarborough.
Seamer died intestate shortly before 8 Feb. 1402, when letters of administration were granted to his son and heir, John. The latter lived on until 1429, in possession of three tenements and various shops in Scarborough.
