Champlain had overwintered in Quebec. Supplies were low, and English merchants sacked Cap Tourmente in early July 1628. A war had broken out between France and England, and Charles I of England had issued letters of marque that authorized the capture of French shipping and its colonies in North America. Champlain received a summons to surrender on July 10 from the Kirke brothers, two Scottish brothers who were working for the English government. Champlain refused to deal with them, misleading them to believe that Quebec's defenses were better than they actually were (Champlain had only 50 pounds of gunpowder to defend the community). Successfully bluffed, they withdrew, but encountered and captured the French supply fleet, cutting off that year's supplies to the colony. By the spring of 1629 supplies were dangerously low and Champlain was forced to send people to Gaspé and into Indian communities to conserve rations. On July 19, the Kirke brothers arrived before Quebec after intercepting Champlain's plea for help, and Champlain was forced to surrender the colony. Many colonists were transported first to England and then to France by the Kirkes, but Champlain remained in London to begin the process of regaining the colony. A peace treaty had been signed in April 1629, three months before the surrender, and, under the terms of that treaty, Quebec and other prizes that were taken by the Kirkes after the treaty were to be returned. It was not until the 1632 Treaty of Saint-Germain-en-Laye, however, that Quebec was formally given back to France. (David Kirke was rewarded when Charles I knighted him and gave him a charter for Newfoundland.) Champlain reclaimed his role as commander of New France on behalf of Richelieu on 1 March 1633, having served in the intervening years as commander in New France "in the absence of my Lord the Cardinal de Richelieu" from 1629 to 1635. In 1632 Champlain published "Voyages de la Nouvelle France", which was dedicated to Cardinal Richelieu, and "Traitté de la marine et du devoir d'un bon marinier", a treatise on leadership, seamanship, and navigation. (Champlain made more than twenty-five round-trip crossings of the Atlantic in his lifetime, without losing a single ship.)