The combat of Siegburg (1 June 1796) was the first move in the French offensive across the Rhine that was meant to be their main campaign of 1796. The French plan, devised by Carnot, was for Jourdan's Army of the Sambre-and-Meuse to cross the Rhine around Dusseldorf to draw the Austrians north, allowing Moreau's army of the Rhine-and-Moselle to cross the Rhine much further south and advance to the Danube.
At the start of the campaign the Austrian armies along the Rhine were all under the command of the Archduke Charles, possibly the best Austrian general of the period. His main force was actually on the west bank of the Rhine, posted between Kreuznach (close to the Rhine) and Baumholder, thirty miles to the west. The Austrians were in this advanced position because they had been on the verge on going onto the offensive themselves before Napoleon's early successes in Italy forced them to move troops from the Rhine front.
Jourdan's first opponents were the Austrian right wing under the Duke of Wurttemberg. This force was posted on the east bank of the Rhine. Two divisions were on the banks of the Rhine at Ehresnbreitstein (opposite Coblenz) and Neuwied (ten miles to the north-west) and two more were at Altenkirchen, twenty miles to the north. His outposts were on the Sieg River, which flows west towards Bonn.
The only Rhine crossing in French hands was at Dusseldorf, thirty five miles to the north of the Austrian front line. The French forces at Dusseldorf were under the command of General Kléber. On 30 May Kléber crossed the Rhine and began to advance south towards Wurttemberg's advance guard. By the end of that day the French had reached the Wipper (a tributary for the Rhine that joins it at Leverkusen).
On 1 June Kléber crossed the River Agger and reached the Sieg. The French advance guard, under General Francois Lefebvre, reached the town of Siegburg, where the Agger flows into the Sieg. The bridge at Siegburg was defended by part of the Austrian advance guard under General Kienmayer.
Lefebvre attacked the Austrian positions, forced them to retreat and captured the bridge. At the same time General Collaud had been sent west to Meindorf where he crossed the Sieg and threatened the Austrian left. The Austrians abandoned the line of the Sieg and retreated just over ten miles south-east to Uckerath.
The Duke of Wurttemberg responded to the French threat by bringing a division up to Uckerath, but when the French threatened that position he retreated back to Altenkirchen where he made his stand (First battle of Altenkirchen, 4 June 1796).