1805 Danube Campaign: Act II - Going Operational (15 - 23 October 1805)

By October 13 French armies had entered Bavaria along multiple axes of advance and several corps were closing in on Munich, where the Elector was still keeping his options open.  A final diplomatic "letter of offer" from the Emperor of the French read, to me, like an ultimatum, and evidently Maximilian Josef read it the same way, or perhaps his francophile inclinations just got the better of him.  At any rate, an alliance was concluded on mutually acceptable terms on the 14th, and the now-Royal Army of Bavaria joined its new French comrades in marching shoulder-to-shoulder to the Inn, where the main Austrian army was presumed (quite rightly) to be awaiting their coming.

The situation on October 13 - all armies visible.

One of the offers made by the Bavarians to the French had been the supply of intelligence gathered from a network of agents and observers around the principality.  They had not much to tell of the Austrians, but a critical piece of news they delivered once the agreement was signed and sealed was the presence of a Russian army less than forrty miles from the capital.  Kutuzov's 1st West Army had crossed the Bavarian frontier on 11 October via the Böhmerwald pass at Weiden.  Proceeding from there to Ingolstadt and then to Freising, it posed an imminent threat not only to the Bavarian state but to the great French supply base being established at Munich to support the war on the Inn.  Soult's IV Corps was the closest as well as the strongest available.  He was immediately ordered to peel off from the advance and supply flank security, locating and stopping the Russians before they could do any harm.  

The situation on the 17th October, as seen by the French

At this point the armies were in sufficiently close contact that we moved to the operational map.  Each hex on the strategic map shown above is about eighteen mile across, and corresponds to a more detailed map divided into a grid of squares in a brick pattern.  Each grid square therefore has six neighbouring squares, just like a hex grid, but also maps neatly to a 2' square area on the tabletop when we get down to grand-tactical battles.

Hex K11, with the river crossings of Freising and Moosburg, on the Isar, as seen on the operational map

Moving now on the operational map, leading elements of the Grande Armée crossed the Inn at Wasserburg on the 17th, siezing the bridge there and slipping a division of Murat's reserve heavy cavalry and some horse artillery onto the east bank before the Austrians knew what was happening.  The Austrians became aware at this point that their diplomatic efforts toward Bavaria had failed, and began to converge their armies east of Wasserburg to prevent a breakout, while at the same time watching for flanking movements to Passau or Rosenheim.

Bernadotte's I Corps, supported by the cavalry, pushed on, driving back Austrian outposts into the hills rising ominously to the east of the valley.  Marechal Ney, along with Bavarian General Wrede, looked for other crossing points to the south.  They took the city of Rosenheim, but found its vital bridge destroyed by the retreating Imperial troops.  Ney set his engineers at once to repairing it, and his scouts to exploring further yet up the riverbank.

Meantime, back in Bavaria, Soult located the main force of the Russians.  Crossing the Isar at Freising, they had advanced in three parallel columns toward Munich, although two of the three columns remained invisible to the French.  The most powerful column was the easternmost, led by Kutuzov himself.  It was marching via Erding to Markt Schwaben up the valley of the river Sempt.  Just north of Markt Schwaben Soult, accompanied by the Emperor, came upon its vanguard on the 23rd, and attacked at once.