By Iron and Blood : Königgrätz 2nd edition

The Battle of Koniggratz (or Sadowa) occurred on July 3, 1866 and involved over 450,000 men from multiple European nations and principalities.

The battle would decide the destiny of Europe, determining whether Prussia or Austria would form a united Germany.

The Prussians under General Helmuth von Moltke invaded Austria in late June of 1866 with three major armies, each following a separate axis of advance. Using divergent approaches was risking defeat in detail, but Moltke counted on superior Prussian maneuverability to outflank the Austrian North Army under Feldzugmeister Ludwig von Benedek.

Battles were fought at Nachod, Tratenau, Skalitz, Soor and Gitschen with the Prussians prevailing in nearly all those encounters. The demoralized Austrians gathered their remaining strength in prepared positions in front of the fortress of Koniggratz, hoping that one last titanic defensive battle would win them the war. The Prussians advanced with the 1st and Elbe Armies, engaging the Austrians. Prussian commanders looked for the approaching 2nd Army, hoping it would arrive in time to deliver the final blow.

But where where were the Prussian reinforcements and how long would it take to reach the battlefield? The race was on – could the Austrian North Army defeat their outnumbered Prussians foes before the 2nd Army closed the vise or would the war end under the walls of Koniggratz?