A pencil inscription on the ebony reverse reads 'wife of John lord Lonsdale. bought from Byram a [...] of Lo[...] ...'.
Lady Katherine Thynne (d. bef. 1713), daughter of Sir Henry Frederick Thynne, 1st Baronet, married the British politician John Lowther, 1st Viscount Lonsdale, PC, FRS (1655-1700), known as Sir John Lowther, 2nd Baronet, on 3 December 1673.
For another miniature of a member of the Lonsdale family, James Lowther, 1st Earl Lonsdale, see lot 395.