Robert and Thomas Wintour is written about the Gunpowder Plot is derived from Thomas's confession, signed on 23 November 1605; details of the so-called Spanish Treason were added three days later. One of only two confessions printed in the "King's Book" (a highly partial contemporary account of the affair), Thomas Wintour's was the only account the government had of a plotter who had been involved from the beginning; Guy Fawkes, weakened by days of torture, may have been at the heart of the group, but he was not at its first meetings. However, Antonia Fraser views the document with suspicion, not least because Thomas's
Robert and Thomas Wintour friends also would with good reason condemn us." He nevertheless agreed to join the conspiracy, and as Catesby had not entirely given up hope of foreign support—"because we will leave no peaceable and quiet way untried"—Thomas returned to the continent. In Flanders he met Juan Fernández de Velasco, 5th Duke of Frías and Constable of Castile, who was holding court there before his journey to England to conclude the Treaty of London. Thomas again stressed the plight of English Catholics, hoping to influence the forthcoming treaty negotiations due to take place at Somerset House in London. The Constable was "friendly