The soldiers, suffering as much as the besiegers, would gladly have brought matters to an issue one way or the other by again assaulting the walls; but their officers restrained them, assuring them that the city could not hold out long, and that they would have an ample revenge when the time came. Life in the city was most monotonous now. There was no stir of life or business; no one bought or sold; and except the men who went to take their turn as sentries on the wall, or the women who fetched the daily ration for the family from the magazines, there was no occasion to go abroad. Fuel was getting very scarce, and families clubbed together and gathered at each others houses by turns, so that one fire did for all. But at the end of February their sufferings from cold came to an end, for the frost suddenly broke up; in a few days the ice on the lake disappeared, and spring set in. The remaining cattle were now driven out into the fields under the walls to gather food for themselves. Strong guards went with them, and whenever the Spaniards endeavoured to come down and drive them off, the citizens flocked out and fought so desperately that the Spaniards ceased to molest them; for as one of those present wrote, each captured bullock cost the lives of at least a dozen soldiers. Don Frederick himself had long since become heartily weary of the siege, in which there was no honour to be gained, and which had already cost the lives of so large a number of his best soldiers. It did not seem to him that the capture of a weak city was worth the price that had to be paid for it, and he wrote to his father urging his views, and asking permission to raise the siege. But the duke thought differently, and despatched an officer to his son with this message: "Tell Don Frederick that if he be not decided to continue the siege until the town be taken, I shall no longer consider him my son. Should he fall in the siege I will myself take the field to maintain it, and when we have both perished, the duchess, my wife, shall come from Spain to do the same." Inflamed by this reply Don Frederick recommenced active operations, to the great satisfaction of the besieged. The batteries were reopened, and daily contests took place. One night under cover of a fog, a party of the besieged marched up to the principal Spanish battery, and attempted to spike the guns. Every one of them was killed round the battery, not one turning to fly. "The citizens," wrote Don Frederick, "do as much as the best soldiers in the world could do."