The siege and capture of Calais followed, and then by the mediation of the Pope peace was made, and for a time preserved. Petty hostilities however never ceased in Brittany, and finally in 1355 the war broke out anew. Three armies were fitted out,--one of a thousand men-at-arms under the Black Prince for operations in Guienne, a second under the Earl of Derby for Brittany, and a third under the personal command of the King. Little, however, was effected in the campaign of 1355. The King was recalled to England by an invasion of the Scots, and the operations of 1356 in Brittany were checked by the appearance of the French King in superior force. But at the close of July the Black Prince suddenly started on a wild raid from the Dordogne in the south to the Loire. His object seems to have been to effect a junction with Derby's forces at Orleans; but it is difficult to see how he could have hoped for success. He had reached Vierzon on the Cher when he heard that the King of France was on his way to meet him in overwhelming strength. Unable to retreat through the country which he had laid waste on his advance, he turned sharp to the west down the Cher and struck the Loire at Tours. There for four days he halted, for what reason it is difficult to explain, since the delay enabled the French to cross the Loire and seriously to threaten his retreat. There was now nothing for the Prince but to retire southward with all haste. The French were hard on his track, and followed him so closely that he was much straitened by want of supplies. On the 14th of September the English were at Chatelheraut and the French at La Haye, little more than ten miles apart, and on the 15th the French made a forced march which brought them fairly to southward of the Prince, and between him and his base at Bordeaux. All contact however had been lost; and the French King, making sure that the Prince had designs on Poitiers, swung round to the westward and moved straight upon the town. On the 17th, while in full march, his rearguard was suddenly surprised by the advanced parties of the Prince. As in the movements after the Alma, each army was executing a flank march, quite unconsciously, in the presence of the other. The French rearguard pursued the reconnoitring party to the main body of the English, and after a sharp engagement was repulsed with heavy loss. The French army had actually marched across the line of the Black Prince's retreat, and left it open to him once more. [Sidenote: Sept. 18.]