Measures were immediately taken to surround the city and suburbs with redoubts, and to form an entrenched camp. Several thousand workmen immediately commenced this extensive work, and an heroic determination to hazard life and property in the common cause, animated the inhabitants of Nuremberg. A trench, eight feet deep and twelve broad, surrounded the whole fortification; the lines were defended by redoubts and batteries, the gates by half moons. The river Pegnitz, which flows through Nuremberg, divided the whole camp into two semicircles, whose communication was secured by several bridges. About three hundred pieces of cannon defended the town-walls and the intrenchments. The peasantry from the neighbouring villages, and the inhabitants of Nuremberg, assisted the Swedish soldiers so zealously, that on the seventh day the army was able to enter the camp, and, in a fortnight, this great work was completed. While these operations were carried on without the walls, the magistrates of Nuremberg were busily occupied in filling the magazines with provisions and ammunition for a long siege. Measures were taken, at the same time, to secure the health of the inhabitants, which was likely to be endangered by the conflux of so many people; cleanliness was enforced by the strictest regulations. In order, if necessary, to support the King, the youth of the city were embodied and trained to arms, the militia of the town considerably reinforced, and a new regiment raised, consisting of four-and-twenty names, according to the letters of the alphabet. Gustavus had, in the mean time, called to his assistance his allies, Duke William of Weimar, and the Landgrave of Hesse Cassel; and ordered his generals on the Rhine, in Thuringia and Lower Saxony, to commence their march immediately, and join him with their troops in Nuremberg. His army, which was encamped within the lines, did not amount to more than 16,000 men, scarcely a third of the enemy.