In June 1778, Frederick the Great adopted the trench warfare suggested by William and performed brilliantly in Saxony, inflicting heavy damage on the Austrian army led by Marshal Lacy in one battle.
After this battle, Marshal Lacy had to lead the remaining Austrian troops to retreat to Vienna. Upon receiving the news, Joseph II smashed the teacup and was furious and wanted to execute Marshal Lacy. Fortunately, his mother, Queen Maria Theresa, advised the emperor and saved Marshal Lacy's life.
After winning a great victory, Frederick felt that his chance had come. He thought that he did not need to go to Bohemia anymore, but should lead his army directly to Vienna. That day, he wrote a letter to his brother, Prince Henry, ordering Prince Henry to hold back the enemy in front of Bohemia, while he would lead the victorious army directly to Vienna.
After receiving Frederick's letter, Prince Henry was shocked by Frederick's idea, and immediately wrote back to Frederick: My dear brother, it is not the best strategy to attack Vienna at this time. Our army should meet in Bohemia as planned and seize Bohemia. Once the goal is changed to Vienna, even if we win, our army will pay an extremely painful price. Austria and we will no longer have room for maneuver. European countries will definitely not sit idly by and watch us break through Vienna. They will definitely intervene. Prussia has not recovered from the damage of the last war. My brother, I pray that you will preserve the future for Prussia.
But when Frederick received Henry's letter, he was furious. He had never felt that he was so close to Vienna. The idea of avenging the shame of the Seven Years' War was like a dream. Every night Frederick had to grit his teeth and repeat the name of Vienna and that woman before he could fall asleep.
Frederick was unwilling to give up his idea of Vienna, so he wrote to Prince Henry again:
My brother, thank God, I have never felt so close to Vienna. It is like a nightmare that enters my dreams every night to torture me. I must break this city and make everyone in this city kneel at my feet. My brother, for the rise of Prussia, we must wipe out Austria. Now Lacy has been defeated by me. He only returned to Vienna with 20,000 people. I must cherish the opportunity God has given me. My brother, you must obey my orders, you must delay the enemies in Bohemia, and I will immediately join you after I capture Vienna, for Prussia.
Prince Henry had to accept Frederick's orders and change his previous step-by-step tactics to launch a fierce attack on the enemies in Bohemia.
In July 1778, the Prussian army was only 200 kilometers away from Vienna. During this period, Joseph II had to order the Bavarian army to return to Vienna and recruit garrisons from all over the country to form the Vienna Garrison Corps. Joseph II called on the nobles in the Holy Roman Empire to come to the throne, but few responded. They all watched the war between Prussia and Austria.
Before the Prussians arrived at the city, Joseph II ordered the establishment of the Vienna Garrison Corps, which was still under the command of Marshal Lacy. Although Joseph II was very angry about Lacy's defeat, he had to admit that Lacy was the only one in Austria who had the best hope of resisting Frederick.
At the same time, after receiving orders from Joseph II, the Bavarian Front led by Leopold II had to give up their previous advantages in Bavaria and return to Vienna to support it.
However, the process of returning to the rescue was not peaceful. The Prussian cavalry led by Prince Ferdinand of Prussia stuck to their backs like taffy, always giving the Austrians unexpected surprises, greatly delaying the speed of the Bavarian Front's return to the rescue.
In August 1778, the Prussian army, led by Frederick, arrived outside Vienna.
Frederick led a group of generals to a small hill outside Vienna, pointed his whip at Vienna and said:
"My generals, Vienna is right before our eyes, and Prussia's century-old dream is about to be realized in our hands. I ask every soldier to fight this battle with the spirit of sacrificing their lives for the country. When we win, I will distribute the wealth accumulated in Vienna for hundreds of years to every soldier who participated in this war. And you will be respected by all Prussian people. When you are old, you can hug your grandson and proudly tell him that your grandfather followed Frederick to capture Vienna and defeated the Habsburg dynasty that illuminated Europe for hundreds of years, laying a solid foundation for the future of Prussia."
Just as the Prussian army appeared outside Vienna, Marshal Lacy in the city was reorganizing his troops in high spirits.
The 20,000 men who returned to Vienna after the last defeat, the 30,000 men who were transferred from various garrisons by Joseph II, and the 30,000 militiamen in the city totaled 80,000 men. They only had more than 200 artillery pieces, but thanks to the accumulation of the Habsburg dynasty, the army was equipped with the best equipment in Europe, and a large number of horses were transferred to the army, including the royal horses in Joseph II's royal stables.
Although the Austrians had fewer artillery pieces, they were well armed with 30,000 cavalry, including 20,000 cuirassiers, which gave the Austrians confidence in defending Vienna.
After the Prussian troops arrived at Vienna, Frederick ordered a siege of the city. He ordered all the soldiers to dig trenches outside the city to block possible reinforcements from the Austrians. At the same time, the more than 20,000 troops he urgently recruited from the country after the last war were about to arrive. By then, a total of 100,000 Prussian troops would gather under the city of Vienna.
Frederick ordered his soldiers to dig trenches while ordering his artillery to pour shells into Vienna. The Austrian artillery and shells captured in the last war were enough for the Prussian army to use for half a month. There were three trenches in front of his artillery position to prevent the Austrians from making a surprise attack.
Joseph II urgently summoned Marshal Lacy and said:
"My Marshal, I can forgive you for the failure in the last battle, but I will not allow you to fail in this battle. This is Vienna, the foundation of my Habsburg dynasty for hundreds of years. My Marshal, the destiny of Austria for a hundred years is in your hands."
And Lacy said to Joseph II:
"My Marshal, I can forgive you for the failure in the last battle, but I will not allow you to fail in this battle. This is Vienna, the foundation of my Habsburg dynasty for hundreds of years. My Marshal, the destiny of Austria for a hundred years is in your hands."
And Lacy said to Joseph II:
"Your Majesty, please rest assured that I will defend Vienna with my life, but I have only one request, that you and Her Majesty the Queen evacuate Vienna."
Queen Maria Theresa on the side said:
"Marshal Lacy, my son and I are not going anywhere. Vienna is our home, and it is the place where the souls of the Habsburg ancestors have returned. There are only two paths before us.
Either the Prussians are defeated by us, and Frederick, who deserves to die in hell, kneels before us. Or His Majesty the Emperor and I are captured by the Prussians, and the thousand-year glory of the Habsburg family is trampled upon.
Marshal Lacy, His Majesty and I have not only entrusted the fate of Austria to you, but also our lives. Please do not disappoint the expectations of His Majesty the Emperor and I."