Wallenstein left Prague on June 4, 1632. On the way to Neustadt an der Waldnaab he united with the Electoral Bavarian army, reached what is now the city limits of Fürth on July 17th and left in the area of today's nature reserve at Hainberg and the district towns of Zirndorf, Oberasbach and Stein (there to the district of Unterweihersbuch). build a huge warehouse. The 16 kilometer fortress landscape with forts, redoubts and battery positions that Wallenstein had built was enormous: around 13,000 trees were felled for around 40,000 poles and 24,000 crossbars, earth huts (for the infantry) and wooden houses (for the cavalry) were built, and huge amounts of earth were piled up for the entrenchments.[2] 31,000 infantrymen, 12,000 horsemen and an entourage of unknown size, but in total around 60,000 people and (initially) 15,000 horses, camped there for 70 days. This was the largest military camp in world history.[3][4] Wallenstein realized that, despite his numerical superiority, it was not advisable to attack Gustavus Adolf in his “fortifications” around Nuremberg. However, he managed to create a blockade ring around Gustav Adolf's army, so that it ran into supply difficulties. The previously undefeated king was detained for six weeks and condemned to inaction.
Source: Wikipedia