John Knox's chaplaincy of the castle garrison was not to last long. While Hamilton was willing to negotiate with England to stop their support of the rebels and bring the castle back under his control, Mary of Guise decided that it could be taken only by force and requested the king of France, Henry II to intervene. On 29 June 1547, 21 French galleys approached St Andrews under the command of Leone Strozzi, prior of Capua. The French besieged the castle and forced the surrender of the garrison on 31 July. The Protestant nobles and others, including Knox, were taken prisoner and forced to row in the French galleys. The galley slaves were chained to benches and rowed throughout the day without a change of posture while an officer watched over them with a whip in hand. They sailed to France and navigated up the Seine to Rouen. The nobles, some of whom would have an impact later in Knox's life such as William Kirkcaldy and Henry Balnaves, were sent to various castle-prisons in France. Knox and the other galley slaves continued to Nantes and stayed on the Loire throughout the winter. They were threatened with torture if they did not give proper signs of reverence when mass was performed on the ship. Knox recounted an incident in which one of the prisoners—possibly himself, as Knox tended to narrate personal anecdotes in the third person—was required to show devotion to a picture of the Virgin Mary. The prisoner was told to give it a kiss of veneration. He refused and when the picture was pushed up to his face, the prisoner seized the picture and threw it into the sea, saying, "Let our Lady now save herself: she is light enough: let her learn to swim." After that, according to Knox, the Scottish prisoners were no longer forced to perform such devotions.