The French Element
Down south, the lifting of the Siege of Vienna freed roughly 70,000 Austrian troops from the capital. In addition, French involvement in the war persuaded the Kingdom of Italy to seek an armistice, freeing more than 70,000 Austrians from the theatre. Combined with a variety of forces mobilized from throughout the empire, there were now over 150,000 Austrians in the field.
In ideal circumstances, the Prussian commander Helmuth von Moltke would have preferred to strike at the Austrians as swiftly as possible. He could still bring 180,000 men to the fight, easily outnumbering and outclassing the Austrian force. However, matters further north precluded such an attack. Berlin would soon be under siege, and his men were sorely needed to defend the capital. Moltke had no choice but to draw back with all due speed.
Meanwhile, Napoleon III moved into Brandenburg with 220,000 men. The main objective for the French Army was to capture Berlin before the men of Moltke's three armies in the south could arrive to defend it. The Prussians, meanwhile, had put together 100,000 reserves. Instead of fighting in the streets of Berlin, which would surely reduce the capital to rubble, the reserve army was ordered to defend the line of the Elbe. This battle would be Prussia's final stand.
Moltke's military genius would prove to have been sorely missed in the planning for the defense of Berlin. Though more reserves were being mobilized everyday, their numbers were not sufficient to defend the entire line of the Elbe. Napoleon's army had dozens of crossings at their disposal all along the hundreds of miles of river. Concentrating the army at a single crossing point would shatter the thin Prussian cordon. It was exactly what they would do.
Napoleon was no great military mind, but he knew to listen to his generals' advice. He thus ordered the concentration of the French Army at Magdeburg, southwest of Berlin. On the 3rd of August, the Grand Armee crossed in force at Magdeburg over five bridges and pulverized the Prussian defenders. The reserve army's southern flank had been turned, and Moltke's armies in Austria - escorted by the king himself - were cut off from Berlin. Three days later, Napoleon invested Berlin with five corps, completely surrounding the capital from all sides. Two corps were posted south in order to forestall the arrival of Moltke. But as events would prove, even this precaution was not needed.
Retreat to Berlin and Battle of Tabor
Moltke's retreat, made more crucial by the presence of King Wilhelm himself, was proving to be no easy affair. All along the exposed lines of communication leading back through Bohemia and Saxony, Austrian probed and prodded the evacuating Prussians. Food and ammunition was increasingly scarce as the French cut them off from Berlin, severing the Prussian Army's main supply line. As their movements slowed, Moltke knew that he would eventually have to turn and face the harassing Austrian troops in his rear. If they followed his men all the way back into Brandenburg, Moltke and the king would be truly cornered, with the French pressing from the west and the Austrians from the south.
However, Moltke's mantra of concentrating several separated armies and corps to force a decision could not possibly work as well as well in a defensive battle. The Prussian armies had been following a single line of retreat, and therefore a massive flanking maneuvre like that which had won the day at Koniggratz was unfeasible. On the 10th of August, the Prussian First Army halted its retreat at Tabur, and turned to face the enemy. The Army of the Elbe and Second Army, with some divisions as far away as the outskirts of Prague, were ordered to march back south to assist.
What followed was one of the 19th century's bloodiest battles. In its early stages the battle was a struggle by both sides to concentrate enough men to force a decision. The First Army took a heavy beating in the initial fighting, facing the bulk of the Austrian forces alone. As the day wore on, more Prussian reinforcements joined the battle, the individual corps of the other Prussian armies rushing south as swiftly as possible. The Austria army had the advantage of numbers, but the earlier stages of the war had robbed it of its heavy guns and many experienced veterans. Prussia's superior Dreyse needle gun far outclassed its Austrian counterpart, and Moltke's men were better trained to boot.
In the end, these factors tipped the scales in Prussia's favour. Trusting in their weight of numbers, the Austrians mounted wave after wave of infantry charges against the Prussian lines. Though they gained some early success when the First Army fought alone at Tabor, the arrival of fresh troops reversed the situation, and by evening the Prussians were in position to mount a counterattack that could devastate the demoralised Austrians. However, their single line of operations did not allow Moltke to launch the sort of flanking maneuvre that could have trapped the Austrians and wiped out their army. The Emperor's troops thus withdrew more or less in good order.
Moltke had won a tactical victory. But the losses incurred were heavy, and his retreat into Brandenburg was delayed by several days - days that eventually cost Prussia the war.
The Fall of Berlin
On the 13th of August, with the remaining Prussian reserves mopped up in Brandenburg and serious Polish civil unrest in Posen tying down many Prussian troops, the time was right to strike the decisive blow. Only 20,000 defenders were left in Berlin, no match for the 180,000 Frenchmen bearing down on them. After some heavy initial fighting which devastated parts of the Berlin suburbs, by the third day of the assault the Prussian commanders surrendered in person to Napoleon III.
Otto von Bismarck, forever the pragmatist, now began fervently beseeching his king to ask for an armistice. In his view, the sheer weight of numbers stacked against them was insurmountable, and ending the fight now would give them a better position at the bargaining table.
Of course, this was advice that could not be followed. To surrender while Prussia's three main armies remained undefeated would be the greatest humiliation they could possibly suffer. Memories of the Napoleonic drubbing suffered all those years past had yet to fade. They had to fight on. After all, as many had said, Prussia was a military with a state, not a state with a military.
Bismarck's voice could not shout down the clamor among the generals to fight on. But apart from the field armies making their way back to Brandenburg, the morale of the Prussian forces was swiftly disintegrating. For the second time in sixty years, a man named Napoleon had swept into Berlin. The irony was plain to all and painful to most. All across the land Prussian garrisons were surrendering to the French, like they had in 1806. There was no longer an effective high command, as communication from Moltke and the king was thoroughly cut off. The three armies headed north were effectively rebels trying to win back their homeland.
Bismarck knew there was one hope - Russia. Russia was as always the unknown element. France had, after all, gone to war with Russia just a decade prior. Surely they would consider throwing in their lot with France's enemies.
The Russians did consider it. But the Tsar was as usual thoroughly uninterested in European affairs. In the War of 1866 he saw only a chance to use the distraction to seize land from Turkey in the south. Prussia, it seems, was not high on his list of priorities.
So the Prussian Armies trundled on. Helmuth von Moltke's newly improvised plan needed the men to strike west of Berlin and threaten enemy communications. Surprise, it was hoped, would win them a battle. These plans were complicated by the fact that French troops by now occupied Saxony, directly on the line of retreat. Moltke's backhanded swipe was becoming more of a dull head on blow.
The French had already been concentrating towards the south in preparation for Moltke's return. On the 15th, some French scouts reported the Prussian main body bypassing Dresden to the east, making for Magdeburg on the Elbe. At once the French army corps wheeled towards their target. One swift blow, as their first emperor once said, will end the war.
Napoleon III was anxious that he should make full use of his numerical superiority in the upcoming battle, pulling troops from their advance positions west of Berlin. They would prove to be needed.
On the 20th, the Prussian advance guard crashed into the French line at Magdeburg. At this stage only the French I and III Corps were concentrated at Magdeburg, due to uncertainty over Moltke's true intentions. But by the afternoon a further five French corps were joining the fight, crossing the Elbe into the thick of battle.
The attack at Magdeburg failed to achieve full surprise. All the men France needed to hold the town were a few hours' march away. By the end of the first day the Prussians had ground to a halt. Napoleon III had 190,000 men across the bridges into Magdeburg by day's end. There seemed little hope for Moltke and his remaining 130,000.
Amazingly, the morning of the 18th saw a furious Prussian assault. Moltke had during the night realised that pretty much the entire French Army had crossed to the Elbe's left bank to fight his men. This gave Moltke the desperate hope that his army could cross to the other side and separate the French from Berlin, carrying out a lightning march to retake the capital.
It is an indication of Prussia's desperate situation that this was the best plan available to them. It was, in any case, utterly hopeless. Though for a time the Prussians managed to hold the nearest bridge and send a division across, the French reserve was well suited to deal with the threat, and more French reinforcements were marching to the battle from all over the countryside. The Prussian assault was broken, and now the French went on the attack. Prussian morale had been shattered, and the battle became a complete rout. King Wilhelm fled with his men, until at a safe distance he regrouped his advisers and composed his armistice plea. The war was effectively over.
Treaty of Frankfurt
Napoleon III and Austria dictated the terms of peace to Prussia at the Conference of Frankfurt. The treaty saw the end of Prussia's military dominance, reducing it for the foreseeable future to the status of second-rate power. It also defined the new status quo in Germany and Italy.