Battle of Ostrach
21 March 1799

Plans of Operation

by Roland Kessinger, Germany

It was clear to the French government that numerical superiority was on the side of the Allies. Therefore three French armies were to advance quickly and beat the Austrians before they got reinforcements from the Russians. The Army of the Danube under General Jean Baptiste Jourdan, 40,000 men strong would invade southern Germany. This invasion would be supported by the small 10,000 men strong Army of Observation under General Bernadotte that would operate around Mannheim on the Upper Rhine. Further south General André Masséna had to attack, with his 30,000 men of the Army of Helvetia (Switzerland), the Tyrol.

Finally General Schérer had to advance with his 60,000 men of the Army of Italy from the Po valley in to Inner Austria as Napoleon had done in 1797. Two more armies, one under Brune in the Netherlands (10,000 men) and one under Macdonald (30,000 men) in southern Italy were not available for the first battles of the new war. They were needed to control the people of the occupied territories far away from the decisive points at the Danube in Germany and the Po valley in northern Italy.

Against these French armies the Austrians had in March 1799 the 80,000 strong Army of Germany under Archduke Charles that held Bavaria. A smaller detachment of this army under FML Friedrich Freiherr von Hotze (25,000 men) was guarding the Alpine Rhine along the Swiss-Austrian border from Lake Constance to the sources of the Rhine. To cover the Tyrol, FML Bellegarde commanded the Army of the Tyrol (45,000 men). The last Austrian Army was the one of Italy under FML Paul von Kray (60,000 men). Kray was waiting for some Russian reinforcements that were under way and were expected to arrive in April.

The Directory ordered, in February 1799, its generals to attack the Austrians at any costs. The national spirit of the French soldiers should compensate for their numerical inferiority (210,000 Austrians against 140,000 French).

In March 1799 the campaign started in Germany and Switzerland. On March 1st , Jourdan crossed the Rhine at Strasbourg with his Army of the Danube. Six days later Masséna started to attack the Austrian position at the Alpine Rhine. So far, war has not been declared.

Masséna’s Attacks

Masséna’s attack in Grisons near the sources of the Rhine was initially very successful. Within a few days he would push the Austrians back to the borders of the Tyrol. His second attack near Lake Constance against the main forces of FML Hotze at Feldkirch at March 6thand 7thwas, however, a failure. Hotze was able to hold his positions. For a few days fighting died down in this area. Masséna had to wait until Jourdan could do something to assist him on the other side of Lake Constance.

Jourdan’s Advance

Jourdan moved slowly forward from Strasbourg into Germany until mid March. On March 6th he had reached a position east of the Black Forest near the source of the Danube. He stayed in this position until March 13thsince war was still not declared. Jourdan knew that the numbers were heavily against him. Furthermore, he didn’t know exactly where Charles would advance. There was information that the main Austrian army under Charles was south of the Danube somewhere in Bavaria but there was still the danger that a larger Austrian corps might advance on the northern (left) bank of the Danube.

Finally, on March 12thwar was declared between France and Austria. Jourdan got this news three days later although he had already started to advance south of the Danube between this river and Lake Constance after having heard of Masséna’s initial success in Grisons.

The Army of the Danube was organised in to five Divisions. The first was commanded by General de Division Pierre Ferino, the second by General de Division Joseph Souham and the third by General de Division Gouvion St. Cyr. Furthermore there was the division “Advance Guard” under General de Division Francois Lefèbvre and the Reserve Division under General de Division Jean d’Hautpoul.

Forming the advance guard Lefèbvre’s division pushed eastwards along the southern bank of the Danube reaching Messkirch on March 15th causing some Austrian posts had to withdraw from Stockach and Messkirch, but hostilities didn’t break out.

The following day the first division under Ferino reached a position near Ueberlingen at the northern bank of Lake Constance. Ferino’s division got the order to march along the lake while Lefèbvre’s division moved along the southern bank of the Danube in a line with Ferino’s troops the next day. The other French divisions followed those two spearheads.

On March 18th Jourdan personally arrived at Pfullendorf. One day later Ferino attacked some Austrian light troops near Markdorf. General de Brigade Tharreau was able to push his troops over the small river Schussen and take 400 Austrian hussars and 70 infantrymen as prisoners. At the same day, March 19th, part of Lefèbvre’s division crossed the Ostrach River at the village of the same name, searching for the Austrians in three directions. One column of Lefèbvre’s division was moving along the main road from Ostrach to Saulgau while another one followed the road to Altshausen and a third weak column moved to Friedberg.

The weak Austrian outposts of the advance guard therefore had to retire to Saulgau and Ratzenreute.

Jourdan’s Intentions

There had been much speculation about the real intentions of General Jourdan at this early stage of the campaign. He had orders to attack the Austrians whenever he could. On the other had it is clear that he knew that Charles’ army was nearly twice as big as his own, so he moved carefully eastwards. The distance he marched between March 13th and March 21st , the day of the Battle of Ostrach, could have been covered in two days. It is obvious that he was not rushing against Charles. He was advancing eastwards, so that nobody could blame him for cowardice, and looking for a good position where he could wait for Charles and his army.

He found his ideal line of defence along the Ostrach River. This small river rises in a marsh south of the village of Ostrach and flows northwards to the Danube. In this marsh another small river, the Rotach has its source and flows southwards into Lake Constance.

The comparatively small distance between Lake Constance and the Danube was another advantage of the Ostrach-Rotach position. Some kilometres further to the east the Danube flows in a curve to the north so that the distance between the Danube and Lake Constance gets larger there.

Jourdan let his army take position behind the Ostrach and the Rotach, pushing part of his advance-guard division further east.

Jourdan was still afraid that Charles might attack his good position along the Ostrach and the Rotach between the Danube and Lake Constance from the northern bank of the Danube. Therefore, he sent out the “Flanquers de Gauche” under General de Division Dominique Vandamme to search for the Austrians in this area. The French generals were afraid that the Austrians might attempt the same manoeuvre as they had done in 1796. When they got news that FML Nauendorf was in Ulm, in early March, they were even more afraid since they believed that this general was usually charged with such outflanking manoeuvres. Jourdan couldn’t know that Charles had decided to attack in a more conventional way.

Austrian Advance

Charles got news of the French crossing of the Rhine on March 3 rd in Bavaria. He ordered his advance guard under FML Nauendorf to cross the Lech River the following day and to take positions between Lake Constance and the Danube near Biberach.

There was an another small detachment of the Army of Germany under FML Sztarray (5 battalions, 6 cos., 20 sqdns.), near Amberg in Franconia, that had to screen the area along the Main River for French troops. After March 3 rd Charles sent out small cavalry patrols from the Danube near Ulm to the north to make contact with FML Sztarray's detachment. The Austrian advance guard arrived near Biberach on March 8th . On the same day, the main Austrian army crossed the Lech.

Meanwhile, Charles was sure that Jourdan had concentrated his forces near the Danube and that there was no danger of a French attack along the Main. So FML Sztarray got the order to rush to Ulm but Sztarray got the letter only a few days later so he was not able to reach Charles in time for the first clashes.

After Masséna's first successful attacks in Grisons, Charles was afraid that Masséna might break through the Feldkirch position directly south of Lake Constance, which would have severely endangered his left wing. Therefore, he sent the two divisions of FML Baillet-Latour and FML Reuss south to link up with FML Hotze near Bregenz at the eastern tip of Lake Constance.

On March 17th FML Hotze informed Charles that there was no longer a danger of a French advance at this position so the two divisions could join the main army north of Lake Constance again. Only three battalions of the Darmstaedter contingent (some Imperial troops) and one battalion of Peterwardein Grenzer remained at Weiler near Bregenz. FML Hotze moved with 8 battalions to Bregenz to support Charles at the north bank of Lake Constance if necessary.

On March 20ththe Austrian army was united in two camps at Altshausen and Renhardsweiler, some kilometres east of Saulgau.

Battle of Ostrach 21 March 1799

Back to Table of Contents -- First Empire #66
Back to First Empire List of Issues
Back to MagWeb Master Magazine List
© Copyright 2002 by First Empire.
This article appears in MagWeb (Magazine Web) on the Internet World Wide Web. Other military history articles and gaming articles are available at http://www.magweb.com