Very few castles were taken by direct assault. Starvation and disease reduced a garrison to the point where they had to surrender or die (Document 40). Chivalric courtesy and elaborate rules surrounded the surrender of a castle—agreements which might or might not be honored by the victors (Documents 36 and 37). For example, the castellan might agree to surrender the castle if relief or reinforcements did not arrive within a certain period of time. Under these circumstances the defending force might be allowed to leave with their arms and honor intact. But often the victorious army failed to keep to the agreement of surrender and slaughtered the entire castle guard. Usually the castellan or lord of the castle left the castle for prison or execution (Document 34). After a long siege the defeated forces might be so debilitated by starvation and disease that they died shortly after the siege was lifted anyway. Treachery was always a possibility, and many castle and city gates were opened by people who expected to receive large rewards for their treachery. Ingenious tricks and disguises also played a part (Documents 43 and 53). Although castles were often turned into prisons in the eighteenth and nineteenth centuries, medieval prisons were small. Writers of romantic fiction have made much of dungeons and torture, but medieval justice was usually direct and swift. Traitors were usually killed before they could escape to enjoy their reward. The only prisoners worth keeping were the wealthy nobles who were held for ransom. For them the great tower made an excellent and secure prison (Documents 37 and 41). Important captives lived in luxury; King John of France lived in a London palace, hunted in the royal preserves, and was not eager to return to France.