Frances Walsingham belonged to the highest echelons of Elizabethan society. The only surviving child of Francis Walsingham, the queen’s Principal Secretary and spymaster, Frances married the poet and soldier Sir Philip Sydney in 1583. After his death from a battle wound only three years later, she married Robert Devereux, 2nd Earl of Essex, Queen Elizabeth’s favorite throughout the 1590s. Until recent technical examination, however, Frances was not firmly identified as the sitter for this portrait. The cartellino—an illusionistically painted label—at upper left was added in the late 16th century but subsequently damaged and overpainted, its original inscription replaced with a false one identifying the subject as Mary Queen of Scots. In 2023, FAMSF conservator Elise Effmann Clifford analyzed faint traces of the original lettering under the microscope and digitally reconstructed the lost text: “The Ladie Sidney daughter/to Secretarye Walsingham.”