Along with The Cardinal, The Traitor is widely considered to represent the finest of Shirley's efforts in the genre, and to be among the best tragedies of its period.
"[1] The Traitor was licensed for performance by Sir Henry Herbert, the Master of the Revels, on 4 May 1631, and was acted by Queen Henrietta's Men at the Cockpit Theatre.
[2] In creating the character of Sciarrha, Shirley may have been influenced by Foreste in Sir William Davenant's The Cruel Brother (1627).
Shirley's source for the play's subplot was the account of the murder of Buondelmonte in Le istoire fiorentine by Niccolò Machiavelli.
[6] In 1819, Richard Lalor Sheil produced an adaptation of The Traitor called Evadne, which was popular in both England and the United States.
One is to frustrate the fortunes of his rival Cosmo by impeding his marriage to the wealthy Oriana; the second is to bring down the Duke by embroiling him in a quarrel with the violent nobleman Sciarrha.
Lorenzo, however, is too crafty to fall into Sciarrha's trap, and feigns ignorance of the matter and pretends to call for the Duke's guards.