As it retreated southeast toward Graz, Jellacic's division passed across the front of Eugène de Beauharnais' Army of Italy, which was advancing northeast in pursuit of Archduke John.

The second French division's arrival secured a clear numerical superiority over Jellacic, who was critically short of cavalry and artillery.

In the opening encounters of the 1809 war between France and Austria, Emperor Napoleon beat Feldmarschall-Leutnant Johann von Hiller at the battles of Abensberg and Landshut on 20 and 21 April.

[4] The following day, Napoleon defeated Generalissimo Archduke Charles at the Battle of Eckmühl, forcing him to retreat through Regensberg (Ratisbon) to the Danube's north bank with the main army.

[6] At the beginning of the 1809 war, Feldmarschall-Leutnant Jellacic's division formed part of VI Armeekorps and consisted of two brigades of line infantry under Generals-Major Konstantin Ettingshausen and Josef Hoffmeister von Hoffeneck.

[7] However, when Bavaria was invaded, Archduke Charles detached Jellacic to advance from Salzburg and occupy Munich on the extreme south flank.

In the clash, a few hundred Hungarian regulars and Grenz infantry repulsed a brigade of pursuing Bavarians under the overall command of Marshal François Joseph Lefebvre.

[15] John split his army, sending Feldmarschall-Leutnant Ignaz Gyulai along a southerly route to Ljubljana (Laybach), while taking his attenuated main body northeast to Villach.

For his part, Archduke John warned Jellacic that Eugene was heading for Bruck an der Mur, 40 km north of Graz.

[2] Jellacic's advance guard arrived at Sankt Michael on the morning of 25 May, and by 9:00 am the bulk of his division had reached a location just to the north.

Jellacic sent his 60 horsemen and General-Major Ignaz Legisfeld's light brigade to hold off the French on a ridge just west of the town.

The French commander also sent two battalions of the 62nd Line Infantry Regiment along the south bank of the Mur to turn the Austrian left flank.

Historian Digby Smith blames the disaster on Jellacic remaining in Salzburg too long and his error in sending away most of his cavalry and artillery.

[2] Austrian army historian Gunther E. Rothenberg calls Jellacic, "a remarkably unlucky and inept general.