The end of the Byzantine Empire.

 Muhammad II, then 21, aims to attack Constantinople, the terminal point of the Silk Road connecting the Black Sea and the East Mediterranean Sea, in order to make Ottoman Turkey the world's largest empire despite opposition from his ministers. But I would like to explain again here what kind of city was Constantinople, which prevented the attack of the Islamic Empire and put the attack of Olgana Igor, the famous monarch of the Kiev Empire, without permission. First of all, Constantinople is in the form of a peninsula protruding from the sea, so attacks from the sea are quite difficult because it is surrounded by the sea on three sides and the walls are built on the breakwater by the water. And to talk about how the only western defense facing the land is, on this side, the walls of Theodosius, which were built in the heyday of the Byzantine Empire, stood tall. The figure below shows an overview of the castle.  The monarchs, surrounded by triple barriers, and also surrounded by outer moats that attracted seawater, were not in history except for the Venetians who completed their leading role in the Fourth Crusade, and it was a natural and wise decision to withdraw the military quickly after Arake (?Igor signed a trade treaty. But this young monarch, Muhammad II, attacked Constantinople in every possible way. According to the records at the time, in order to surround Constantinople, which had only 7,000 troops in total, with a population of 35,000, even at the time of 150,000 troops, it mobilized an unprecedented large army to perfect its siege and maintain an overwhelming advantage on land. Also one of the strategies that King Muhammad II thought of was attacking from the walls around the Golden Horn, east of Constantinople. The walls around the Golden Horn were relatively poor, and Constantinople was temporarily captured by the Fourth Crusade in 1204, and the Latin Empire created by the leaders of the Crusaders was temporarily established, but it was also a decisive blow for the Crusaders to attack the walls on the Golden Horn side. But of course, the defense was also predicting an attack in this direction. The Golden Horn was defended with iron chains installed at the entrance of the bay by Venetian and Genoa merchants who had the best navigation technology in the Mediterranean at the time. Western European merchants valued Constantinople as a cluster of pepper and other trade products coming through the Silk Road, so they were personally fighting against the Byzantine side, considering the size of commercial and territorial losses the city would suffer when it crossed the hands of Muslims. It is Ottoman Turkey, which led nearly 100 sailing ships (there were no navy in Turkey at the time) against the West guarding the Golden Horn with a total of 30 ships, but most of them had never seen them break through the sadness of Italian city-state merchants roaming the Mediterranean Sea. What came to mind from that is the way below. The road to climb the mountain in the direction of Galata on the other side of the Golden Horn was renovated, and after finishing the ground picking, two wooden rails extending from the slope of the Galata to the Golden Horn were laid, and the rails were painted with enough animal oil. And they made a large number of trucks with wheels that fit perfectly on the rails, loaded two sailing ships on top of them, and opened the sail in time for the fair wind, pulling the ship with the power of cows and humans into the Golden Horn in the middle of the night. Thus, Mahomet II, who completely abandoned Constantinople from the sea and from the land, introduced the latest weapon of Ottoman Turkey on the battlefield, was a cannon. Muhammad II was developing cannons through him, citing Urban, who claimed to be a Hungarian who had been criticized for his cannon skills to sell to the Byzantine Empire, advocating that he could break down even the triple walls of Constantinople. At that time, the cannon's firing technology was very inexperienced, so there were many artillery flying away at the same time as the firing, so it was thought that the actual deployment would be realized in the future. Urban started developing cannons that no inland country or maritime country had yet, ignoring the direction of technology development at the time of research to increase the number of launches, and at least, using a shot of destructive power, eventually creating a cannon of 8 m. The destruction of the walls brought about by a series of artillery attacks eventually determined the fate of the siege. Constantinople was eventually captured by the third gun attack of Ottoman Turkey, the last of the 50-day battle. Constantine XI, the last emperor of the Byzantine Empire, drew his own sword and rushed into a swarm of Turkish soldiers like an avalanche and was heroically killed. This completely disappeared the last traces of the ancient Roman Empire, which had had a profound influence on the Western European and Slavic worlds. Now that the Middle Ages are over, the prelude to modern times has risen. With the collapse of the Byzantine Empire, the independence of the Russian Orthodox Church became crucial. Five years before the fall of Constantinople, the Russian Bishops' Conference had already independently elected the archbishop, but after the fall of Constantinople, the Russian Orthodox Church was actually separated from the Greek Orthodox Church. The fall of the Byzantine civilization served as an opportunity to bring independent civilization to Russia. This trend continues until Western Europe later becomes a sample of modern Russian reform.