² The disappearance a posteriori of the two most documented references to Captain Diego Alatriste y Tenorio known to this date is extraordinary. While the testament of Íñigo Balboa and the study of the painting The Surrender of Breda by Velázquez prove that the captain’s image was, for unknown reasons, erased from the canvas on a date later than winter of 1634, we have a first version of a play by Pedro Calderón de la Barca titled The Siege of Breda, and in it, too, there are signs of later manipulation. This first complete version, contemporaneous to the date of the first performance of the play in Madrid—which was written around 1626—and coinciding along general lines with the manuscript copy of the original made by Diego López de Mora in 1632, contains some forty lines that were suppressed in the definitive version. In them explicit reference is made to the death of Colonel don Pedro de la Daga and to the defense of the Terheyden redoubt carried out by Diego Alatriste, whose name is quoted two times in the text. The original fragment, discovered by Professor Klaus Oldenbarnevelt of the Instituto de Estudios Hispánicos at the University of Utrecht, is housed in the archive and library of the Duques del Nuevo Extremo in Seville, and we reproduce it in the appendix at the end of this volume with the kind permission of doña Macarena Bruner de Lebrija, Duquesa del Nuevo Extremo. What is odd is that those forty lines disappear in the canonical version of the work published in 1636 in Madrid by José Calderón, brother of the author, in Primera parte de Comedias de don Pedro Calderón de la Barca. The reason for Alatriste’s disappearance in the play about the siege of Breda, as well as in the Velázquez painting, has to this date not been explained. Unless it was in response to an express order attributable perhaps to King Philip IV or, more likely, the Conde Duque de Olivares, whose disfavor Diego Alatriste may have incurred, again for reasons unknown to us, between 1634 and 1636.