August 29, 1756: The Seven Years War erupts in Europe. The Prussian army led by King Frederick II (later "the Great" to his admirers) invades Saxony. "Blitzing" through the neutral Saxon electorate he hopes to open a path to Austria’s rich Elbe River valley in Bohemia. The Saxon army does not directly resist the invaders but withdraws into a fortified encampment on the Elbe River around Pirna, there awaiting rescue by the Austrians. The Prussian invasion grinds to a halt here; Frederick has no choice but to lay siege. Meanwhile in northern Bohemia, the Austrian army under Field Marshal Browne gathers its strength in preparation for the relief of its new ally.