Kray launched an attack against the French left wing along the Iller River at Erolzheim and Illertissen, but he withdrew his troops when Moreau sent reinforcements.

[1] The Iller River flows north past Memmingen, Erolzheim, and Illertissen in southern Germany and enters the Danube at Ulm.

Another flaw was that the Austrian army's supply services began to break down due to dissension among his staff, leading to low morale and a spike in desertions.

[3] Historian Theodore Ayrault Dodge claimed that Kray's army numbered 110,000 infantry, 25,000 cavalry, and 4,000 artillerists with 500 guns.

The Austrian center led by Friedrich Joseph, Count of Nauendorf numbered 40,000 men and was deployed from Donaueschingen to Villingen.

Saint-Cyr's Center Corps crossed to the east bank of the Rhine at Alt-Breisach, pushed back Ignaz Gyulai's division, and seized Freiburg im Breisgau.

Having drawn Kray's attention away from Moreau's main attack, Saint-Suzanne withdrew to the west bank of the Rhine at Strasbourg.

[12] Lecourbe defeated Joseph Louis, Prince of Lorraine-Vaudémont and captured the Stockach supply base, causing Kray to withdraw north to Messkirch.

[13] Kray moved to the northeast, crossed to the south bank of the Danube at Riedlingen, and marched east to protect his magazine at Biberach.

At about this time, Lazare Carnot delivered the orders of the French government to detach a strong reinforcement to Italy, so 15,000 troops were sent under Bon-Adrien Jeannot de Moncey.

[17] Moreau reorganized his army, sending Saint-Suzanne and one of his division commanders, Joseph Souham, to the lower Rhine to take charge of reserve troops.

On 5 June, Kray mounted an attack against Richepanse's flying left wing[18] in the area of Erolzheim and Illertissen.

[2] In the Battle of Erolzheim, Archduke Ferdinand Karl Joseph of Austria-Este commanded the main column of 23 battalions and 26 squadrons, but "was not favored by the luck of arms".

Baillet's column successfully ousted Louis Michel Antoine Sahuc's French brigade from Balzheim and Wain on the west bank of the Iller.

[20] Johann Rudolf von Sporck, who commanded the reserve, was captured by a French patrol while carrying out a personal reconnaissance.

[2][note 2] On 9 June 1800, Moreau received news that Bonaparte's army occupied Milan; this spurred him to make a new effort.

[17] Moreau realized that Kray would not budge unless he mounted a serious threat to the Austrian line of communications leading back to Vienna.

Grenier's left wing included the divisions of Ney, Louis Baraguey d'Hilliers, Claude Juste Alexandre Legrand, and Jean-Louis-François Fauconnet.