The siege of Glogau (15 March-27 May 1813) was a rare example of a successful French defence of one of the isolated fortresses left behind by the retreat from Poland and eastern Germany at the start of 1813, and saw a sizable garrison hold out for three months before the siege was lifted in the aftermath of the battle of Bautzen (War of Liberation of 1813).
When Prince Eugène de Beauharnais reorganised what was left of the French army after the retreat from Moscow, he placed the survivors of IV Corps in Glogau, on the upper Oder. By 20 February the garrison was 4,000-5,000 strong, and unlike the other fortresses on the Oder and Vistula remained in communication with the rest of the army well into March. Command was split between General Jean Grégoire Barthelemy Rouger de Laplane, governor of Glogau, and adjudant-commandant Durrieu, commander of the garrison, with General Dode as director of engineers.
Glogau was protected by modern fortifications. The main town was on the left bank of the Oder, with a smaller suburb on the right bank. The main town had two lines of fortifications, and a separate star fort just upstream of the main town. The suburb was protected by a single set of fortifications, but these were protected by water. At this point the Oder flows from east to west, so the main town is on the south bank, the suburbs on the north bank.
Glogau was blockaded by the Russians on 15 March. The besiegers, 8000 infantry, 2,000 cavalry and 20 guns were commanded General St-Priest, a French exile in Russian service. Soon after his arrival he summoned the garrison to surrender, but they didn’t answer. On 30 March the Prussian General Scholler made a second summons, this time backed up by the fire of sixteen large caliber guns, and the threat of exile in Siberia, but again without success.
The defenders of Glogau weren't passive. On 31 March they silenced the Prussian guns in a sortie. However Scholler continued to receive reinforcements as the Prussian army mobilised, and the garrison was confined to the fortress until 30 April.
At 1am on 1 May a Prussian force carried out a sharp and unexpected attack on the French bridgehead on the right bank of the Oder, sending two fire ships into the piles of the bridge over the Oder. The attackers reached the abatis of the French position, but were unable to progress any further and were forced to retreat after suffering some loses.
On the night of 6-7 May the attackers opened a trench, which reached within 100 yards of the covered roads of the star fort. The garrison carried out a sortie on 7 May, and after some heavy fighting managed to fill in these siege works.
On 17 May some Allied siege guns arrived from Breslau. On 21 May the Prussians attempted to destroy the river bridge with these guns, but 300 of the defenders crossed the bridge from the main square to the northern suburb, crossed the abatis and destroyed the Prussian gun battery. On the next day the siege artillery was sent back to Breslau.
By now events elsewhere were making the Prussian position at Glogau untenable. The main Allied armies suffered a heavy defeat at Bautzen on 20-21 May and retreated east into Silesia, taking up a position well to the south of Glogau. The French advanced on a wide front, and Victor's II Corps, which had missed the battle, soon approached Glogau. The blockade was lifted on the night of 27-28 May, and II Corps arrived outside the city on 29 May. By the end of the siege 4,000 French troops remained, and they were said to have been in a rather better state than at the start of the siege, the survivors of 1812 having had time to recover and the new recruits gaining experience.
Glogau was besieged for a second time between September 1813 and 10 April 1814, once again with General Laplane in command. This time there would be no relief, as Napoleon had been forced to retreat into France after suffering defeat at Leipzig (16-19 October 1813) but the garrison was able to surrender with the honours of war, and returned to their various homes.