While in prison, he received the news as to his wife's pregnancy. A fellow prisoner, Sir John Trailly, later reported to the 1407 inquiry of Pembroke's reaction. He was not, Trailly said, happy at the news as one might expect; rather, he was moved to anger, as now he had a son, if that son died without heirs, Pembroke's careful planning against Grey might be undone. A few months later, possibly after negotiation with the King of France, King Henry II of Castile agreed to sell his right to Pembroke's ransom to the Constable of France, Bertrand du Guesclin, for 120,000 francs. To do so, du Guesclin had to sell his Spanish lordship of Soria and Molina (which he had previously captured from Spain), back to the King. Pembroke's agreement with du Guesclin laid down that he would pay him 50,000 francs immediately, and the remainder within six weeks of Pembroke's arrival back in England. Pembroke's imprisonment was to continue for another three years, however, as—despite Pembroke's supposed close connections at court and with the King—there was little progress made in arranging for Pembroke's ransom, until early 1375. Meanwhile, Pembroke's own circumstances were especially harsh. He was lodged at Curiel Castle in conditions bad enough to break his health.