An unidentified sitter
[The portrait does not appear in any of the twelve volumes of the Silvy daybooks in the archives of the National Portrait Gallery in London, so the sitter remains unidentified. The sitting probably took place between July 1863 and June 1864, the period covered by the missing volume of the daybooks.]
The carte was acquired at the same time as the adjacent portrait, which has the same backdrop and a similar arrangement of props. The footstool seen near the lower left-hand corner of the image hasn't been moved at all between the two sittings, nor has the ledger under the table. It therefore seems likely the two sitters visited the studio together and were probably related to one another.