The French declared war before their troops were in position to invade Germany. The Germans, commanded by Field Marshal von Moltke, began to assemble into three armies, which were to invade France and to occupy Paris. On 4 August they crossed the frontier, where 3rd Army conquered the walled city of
Wissembourg. Two days later they defeated the French again at
Wörth. On the same day 2nd Army was marching westward, even though one of its corps was still on the railroad. When Napoleon III arrived to take command of the French field army, he followed the urging of his generals and ordered General Lebœuf to besiege
Saarbrücken. Following a vigorous defense, the outnumbered Germans evacuated the city, which the French occupied without crossing the river
Saar. Lebœuf had been warned by his chief intendant, Charles Joseph Francois Wolff, not to cross the Saar because they would be unable to supply men on the further bank. Therefore, the armies of France, led by Field Marshal
Bazaine, took up defensive positions that would protect against every possible attack, but which also left their armies unable to support one another. Moltke assembled his forces into two wings. On the right, 2nd Army, with 134,000 men under Prince
Frederick Charles of Prussia containing the
III,
IV,
IX,
X,
XII Corps, and the Prussian
Guard, advanced towards Saarbrücken. The 1st Army's 60,000 men under Steinmetz, consisting of the
I,
VII and
VIII Corps, was moving in line with 2nd Army from the
lower Moselle river towards
Saarlouis. The Germans crossed the frontier on 4 August. They encountered lively opposition
before Wissembourg which they subdued by bringing up artillery. The battle at Spicheren had not been planned by Moltke, who wished to keep Bazaine's army along the Saar river until he could attack it with the 2nd army in front and 1st army on its left flank, while 3rd army was closing towards its rear. However, von Steinmetz disobeyed and made an overzealous, ill-considered move, leading 1st army south from his position on the
Moselle straight toward the town of
Spicheren, in the process cutting Prince Frederick Charles off from his forward cavalry units. The 1st Army advance guard, the (
14th Division,
VII Corps) under General
Georg von Kameke advancing west from Saarbrücken on the morning of 6 August found the bridges still intact and seized the opportunity to occupy the high ground just beyond the town. The French II Corps under General
Charles Auguste Frossard had abandoned these heights in order to take up what he considered to be a
position magnifique, a fortified line between Spicheren and
Forbach. Frossard distributed his corps as follows: holding the right and centre was the 3rd Division of General
Jules de Laveaucoupet, which was deployed along the heights, with two companies entrenched on the Rotherberg. On the French left General
Charles Nicolas Vergé's 1st Division occupied
Stiring and the Forbach valley. General
Henri Jules Bataille’s division was held back in reserve around Spicheren; in all, counting the corps cavalry and artillery, some 27,000 men with 90 guns. ==Battle==