In the Seven Years' War, Sprecher distinguished himself during the Siege of Prague, by leading an assault on the Prussian line[6] whereupon he was appointed general of the artillery in 1757.
Shortly after the Battle of Leuthen, the garrison was augmented with Austrian troops, and subsequently besieged by Frederick the Great and his army on 7 December 1757.
[11] A court assembled to consider the terms of his capitulation ended with complete exoneration for his actions, and the Empress promoted him to field marshal.
On the way to take command of the Austrian army corps destined to fight in Saxony, he became ill on his way to Prague, and died in Aussig.
Some sources misidentify the commander of Breslau as Johann Andreas Sprecher von Bernegg (1702–1765),[2] but this was his younger brother.