The battle of Blumenau (22 July 1866) was the final battle of the Austrian phase of the Austro-Prussian War and saw the Prussians attack an Austrian position north-west of Pressburg (now Bratislava), continuing the battle even after news arrived that an armistice was due to come into effect later on the same day.
In the aftermath of their defeat at Königgrätz the Austrians, under Field Marshal Benedek, had retreated east to Olmütz, where they hoped to rest and recover. However the Prussians quickly moved south towards Vienna and south-east to Brünn (south-west of Olmütz). At the same time the Prussian First Army was in direct pursuit of the Austrians. Late on 11 July Benedek ordered his army to prepare to move south down the March valley towards the Danube, where they could join up with fresh Austrian troops around Vienna and victorious troops returning from Italy.
As so often happened during this war the Prussians moved too fast for the Austrians. On 15 July the Prussian I Corps and Hartmann's Reserve Cavalry (both from the Crown Prince of Prussia's Second Army) attacked the Austrian columns at Tobitschau. The Prussians blocked the road west of the River March and briefly cut the railway east of the river, but the Austrian held on to Prerau, and this part of the road south remained open. Much further south troops from the Prussian 8th Division cut the railway north of Göding, and it was this attack that really blocked the March route for Benedek.
Benedek decided to move his army east across the Carpathian Mountains, which ran north-south to the east of the March. Once on the eastern side of the mountains the Austrians would move south towards Pressburg, where the mountains met the Danube. This move was carried out with some skill, and by 17 July the Prussians had lost contact with the Austrians.
Moltke decided to resume the advance south. The Army of the Elbe was ordered to move to Znaim, and then towards the Danube at Vienna and points further west. In the centre the First Army was to follow the railway south towards the Danube, with orders to prevent the Austrian troops around Vienna from joining up with Benedek's forces approaching Pressburg. On the Prussian left the Second Army would support the First Army. Moltke was also worried that the Austrians might attack from the direction of Vienna, and so had to guard against that possibility.
By 20 July the leading troops from Benedek's army, Henriquez's Brigade, was only twenty file miles from Pressburg, and it was ordered to rush south-west to reinforce Mondl's Brigade, the only Austrian troops present in the city. Henriquez's men arrived in time to support Mondle when the Prussians attacked. At the same time Benedek was finally removed from command of the army and ordered back to Vienna to face an enquiry into his conduct. On the Prussian side the First Army reached the area between Weikendorf and Schönkirchen, about twenty-five miles to the northwest of Pressburg.
Moltke created a smaller task group for the attack on Pressburg. This included the 7th Division , 8th Division (General Bose) and the 2nd Cavalry Division (General Hann), all under the command of General Fransecky. This gave him 18 infantry battalions, 24 cavalry squadrons and 78 guns.
On 21 July the Prussians carried out a reconnaissance towards Pressburg, and found the approaches weakly defended, with only one infantry battalion and some cavalry at the villages of Blumenau and Kaltenbrunn, north-west of the city.
While these military preparations were underway, the diplomatic efforts finally bore fruit. An armistice was agreed, to come into effect at noon on 22 July. Sadly this news didn't reach the HQ of the First Army in time, and at 3am on 22 July approval was given to the planned attack.
The Austrians had a strong defensive position at the villages of Blumenau and Kaltenbrunn, but their right flank was only protected by the foothills of the Carpathians. General Fransecky decided to attack around the Austrian right flank. General Bose, with the 15th Brigade (31st and 71st Regiments) was to advance across the mountains and get between the Austrian defensive position and Pressburg. At the same time the 7th Division would attack the Austrian position from the front to pin the defenders in place.
The 7th Division attack began before the outflanking move. The Austrians had a strong defensive position outside Blumenau, and the first Prussian cavalry probes were withdrawn. Fransecky was now worried about the slow start to the outflanking move decided to send more troops against the main Austrian line. These troops were to attack the Austrian flanks.
Just after these orders were issued, Fransecky finally learnt of the armistice. This was to come into effect at noon, in only a few hours time, and so his attack had little or no purpose. The Prussian military didn't like having their freedom of action limited by the diplomats, and so he decided to take advantage of his freedom of action to continue with the offensive.
By 9am the Prussians were making progress on their right, where they were close to Kaltenbrunn. The attack on the left was doing less well and the outflanking move was still progressing slowly.
At 10am Fransecky still had no idea where Bose was, and so he ordered a general assault. This pushed the Austrians back some way, and came at the same time as the delayed start of the outflanking attack. Bose's men quickly captured a key hill, and then cut the rail and road links between the Austrian front line and the city. Bose posted one battalion to stop any attack from Pressburg, and then turned west to hit the main Austrian line from the rear. The main Austrian force was now almost surrounded, but the armistice now came into effect, and the fighting slowly died down.
The original terms of the armistice had included final positions for both sides. Bose was well behind the agreed Austrian lines, but in order to acknowledge his victory the Austrians agreed to let him camp on its final positions for twenty four hours. They then withdrew to rejoin the rest of the Prussian army.
The battle of Blumenau cost the Prussians 27 dead, 169 wounded and 11 missing. The Austrians lost 61 dead, 245 wounded and 184 missing. If the battle had been allowed to continue all day then the Austrians would probably have been forced to surrender, but the Prussian commanders knew that they would have to stop at noon, and there was almost no chance that Pressburg could have been captured that quickly.