The Duchy of Saxony-Lauenburg, known as the Duchy, actually has an area of just over 1,200 square kilometers, which is only the size of a county in later generations. Compared with those large principalities that often cost thousands of square kilometers or even tens of thousands of square kilometers, the Duchy of Saxony-Lauenburg is really weak. Therefore, in the House of Princes of the Holy Roman Empire, the Duchy of Saxony-Lauenburg had no say, and was similar to that of ordinary Shells.

However, even if it wants to expand, it will not be so easy. Because, on the north side of the Duchy of Saxony-Lauenburg is the Duchy of Holstein, to the northwest is Hamburg, and on the other side of the river is the Duchy of Brunswick-Lüneburg...... Either one, it's not something it can afford to mess with. Even if the land area of the Free City of Hanseatic Hamburg is not as large as that of the Duchy of Saxony-Lauenburg, the people have more financial resources, and in this era of mercenaries, their strength is much stronger than that of the Duchy of Saxony-Launburg.

Coincidentally, the turmoil in the North Sea gave the Duchy of Saxe-Lauenburg across the river an opportunity for expansion, with the south-eastern province of Bremen just across the Elbe River from the Duchy of Saxony-Lauenburg. As long as the coalition can defeat the North Sea State, they will have a chance to gain some of the land in Bremen Province......

Unfortunately, the coalition was defeated, and the expansion of the Duchy of Saxony-Raunburg came to an end, and Marin led his troops to the door......

In fact, Brunswick-Lüneburg, the capital of the Duchy of Lüneburg, is not far from the capital of the Duchy of Saxony-Launburg, just across the Elbe River, and then more than ten kilometers to the southwest.

However, Marin chose to go to the east bank of the Elbe first, and settle for Lauenburg, the capital of the Duchy of Saxony-Lauenburg on the Elbe.

Why? Marin feared that if Lüneburg were attacked first, the people of the Duchy of Saxony-Lauenburg, especially the royal family, would be so frightened that they would abandon the city and go into exile. In this way, it is very troublesome.

Therefore, Marin chose to besiege Lauenburg first, and capture the family of Magnus I, Duke of Saxony-Lauenburg, before saying that, lest they go into exile.

As for whether the Duchy of Braunschweig-Lüneburg would abandon the city and flee when it learned that his army was heading south? Marin wasn't worried. Because, the city of Lüneburg is much taller and stronger than the city of Lauenburg, and it has been replaced with a heavy iron gate, which is not afraid of bursting with powder kegs. Therefore, the Welf family will definitely not give up the city of Lüneburg easily.

Moreover, Lüneburg is a famous salt-producing and farming area in Germany, and it is the salt city of Germany. At the beginning, the Duchy of Saxony-Lauenburg on the other side of the river built the Stocknitz Canal from Lauenburg to Lübeck in order to facilitate the smooth transportation of Lüneburg's mineral salt to Lübeck in the Baltic region, and then sell it to Poland and Lithuania, where salt prices were very high.

It can be said that sitting on the salt mines of Lüneburg, the Welf family will not have to worry about eating and drinking. They would never give up Lüneburg, the city of salt mines that produced "white gold", table salt, unless they had to do it as a last resort.

Therefore, Marin simply sent men to besiege the small town of Lauenburg on the east bank of the Elbe, so as not to run away from Magnus I's family.

……

When Marin led an army of 30,000 to surround the small Lauenburg regiment, the remaining soldiers and civilians of the Duchy of Saxony-Lauenburg in the city were frightened......

Magnus I himself took more than 3,000 soldiers and horses with him, and those who remained in the city of Lauenburg were only seven or eight hundred old and sick, and two or three thousand strong people. For Marin's army of 30,000, there was no resistance.

Moreover, because of the average financial resources, the gates of Lauenburg have not been replaced by large iron gates, and they are still the most ordinary oak gates.

What to do with the oak gates? Gasoline, of course......

Marin directly asked people to carry a mixture of gasoline, pour it on the firewood and grass piles that had been piled up under the city gate in advance, and then light the fire......

After the fire was extinguished, the west gate of the city of Lauenburg was directly burned to the ground. Marlin sent another demoman forward and blew up the pile of debris behind the door......

Seeing that the city gate was lost and Marin's tens of thousands of troops were about to swarm in, Madame Catherine, the wife of Magnus I, who knew that she was powerless to resist, came out crying and surrendering with her two-year-old son Prince Francis and a group of ministers who stayed behind......

It should be noted that Madame Catherine, the wife of Magnus I, was none other than the daughter of Henry, Duke of Wolfenbüttle, in Braunschweig. Otherwise, the Duchy of Saxony-Lauenburg would not have easily responded to the call of Henry, Duke of Braunschweig-Wolfenbüttle, to deal with the North Sea Kingdom together. Even with territorial ambitions for the North Sea State, Magnus I had little confidence and hesitated. It can be said that he was also cheated by his father-in-law this time......

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After capturing Magnus I's wife and children, Marin's goal was basically achieved. As for Magnus I's two brothers, Eric and John, they were not in Lauenburg. Because both of them are clergy of the church, and they are bishops in other places. Marin didn't want to arrest them either, after all, they were all monks, and they would not have the right to inherit, and it would not affect Marin's rule over the Duchy of Saxony-Lauenburg.

Besides, Marin did not intend to kill Magnus I and his sons, but only placed them under residential surveillance, similar to the later Manchu Dynasty's captivity (delimiting the scope of activities) of the Ming dynasty. As long as their father and son did not die, his brothers would not be able to inherit the title of Duke of Saxony-Lauenburg and fight against Marin.

After capturing Lauenburg and catching the people he wanted to capture, Marin left only a few hundred garrisons, and then directly led his troops across the river to Brunswick, the Duchy of Lüneburg, on the other side of the river. As for the rest of the Saxony-Lauenburg principality outside of Lauenburg, Marin was in no hurry to occupy it. It is much more important for him to seize the members of the country's ruling family than to occupy territory......

After crossing the river, Marin's army of 30,000 marched more than ten kilometers and surrounded the city of Brunswick, the capital of the Duchy of Lüneburg.

However, Prince Otto, son of Henry, Duke of Brunswick-Lüneburg in the city, was not too worried. His mother, Margaret of Saxony, had sent to Switzerland to find his uncle, Frederick III, Elector of Saxony, and asked for help.

The 17-year-old Prince Otto believed that as long as his uncle, Frederick III, who was the leader of the German princes, came forward, Marin would have to give face no matter what. Of course, the premise is that he can hold out until his uncle arrives from Switzerland.

However, Prince Otto was not worried. Because, there were still 4,000 regular troops in the city of Lüneburg. In addition, more than 7,000 people with certain training experience were recruited to assist in defending the city.

The walls of Europe are much stronger than those of ancient China. For most of their walls were made of stone. Unlike ancient China, many cities were built of bricks, and the two were not the same degree of solidity.

In addition, the four heavy iron gates also gave Prince Otto enough confidence. As long as he did not allow the Beihai army to storm the city wall easily, he was confident that he would be able to hold out until his uncle Frederick III came to relieve the siege......

……

However, Prince Otto was still thinking too simply......

"On the royal water!" Seeing the large and sturdy iron door, Marin was not stressed.

Then, a cart with aqua regia was carefully pushed over......

Aqua regia is a powerful potion that can corrode gold and silver, and can only be bottled in glass bottles. But glass bottles are fragile, so the people who transport aqua regia must also be careful to avoid accidents......

After the aqua regia arrived, the soldiers in charge of using the aqua regia put on gas masks, carried a few bottles of aqua regia, got into an iron car, and rushed to the city gate......

This kind of iron car is actually modified from Yu Dayou's chariot. That is, a tin roof was added to the wheelbarrow to protect it from bows and arrows and stones on the head of the city. Of course, this kind of tin roof is much stronger than ordinary tin sheds, and can resist stones, so that soldiers who use aqua regia will not be harmed......

Protected by a wheelbarrow with a tin roof, the soldiers using aqua regia reached the gates and began to corrode the gates......

……

Because there was information in advance, the relevant soldiers directly poured the regia water on the iron gate at the established height. Under his careful control, it only took an hour for Wang Shui to corrode through the latch of the large iron gate at the east gate of Lüneburg.

And to the surprise of the soldiers responsible for corroding the iron gate, after corroding the latch of the big iron gate at the east gate of Lüneburg, the city gate was directly pushed open......

It turned out that Prince Otto was confident that the big iron gate could withstand the shelling and impact, so he did not pile up logs, masonry and other debris in the gate hole behind the gate. After corroding the latch, the soldiers using aqua regia easily pushed open the eastern gate of Lüneburg without hindrance......