تاريخ إسبانيا
Massinger's source for the original drama about Sebastian was likely Edward Grimeston's "General History of Spain" (1612). The original version of the play must have treated one of the Sebastian pretenders as genuine. There were at least four such pretenders, and men were executed in 1594 and 1605 for claiming to be the Portuguese king. For the revised version, Massinger used Sir Walter Raleigh's "History of the World" and Plutarch's "Life or Titus Flaminius."