Constantinople (The old name of Istanbul) was capital of the Byzantine Empire. Mehmed II, the Sultan of Ottoman Empire had a dream. He thought Istanbul was a wonderful city. He really wanted to conquer Constantinople. In the beginnings of the 1400's Ottoman Empire was rising. They started to conquer many country in Europe. In that years the Europeans started to beware. They knew the Ottomans could conquer everywhere in the Europe, but still the Ottomans couldn't conquer the most important city of Europe. That city was Constantinople. That city was controlled by the Byzantine Empire. That country was one of the strongest country at the World. But after Ottoman Empire's rising, they started to lose their lands in Europe and Anatolia. Constantinople had a land both in Europe and Asia. The Ottomans conquered the Asia part, but the Europe side was still in Byzantine Empire. Constantinople's geographic strategy was very important, so Ottoman really wanted to control that city. Because they knew that Constantinople was capital of all of the World. Byzantines knew something. If they lose Constantinople, they will dissappear from the World. Their names will only stay in the history pages. Because Constantinople was their capital city and they didn't have many land in Europe. Before the Fall of Constantinople, the world's map was like that.
The Byzantine Emperor was sure that they won't lose their capital city. Because they had a long chain under the sea. It was blocking the entrance of Ottoman's ships. Also they had unquenchable fire under the sea. It can easily burn the Ottoman's ships. They repaired their castles and walls. Also they wanted help from other Europeans. Many of the Europeans didn't want to see the Ottomans in Constantinople, because they knew the Ottomans could become more and more strong, so they accepted to help to Byzantines. On the other hand the Ottomans prepared many ships. Also they built a casttle on the Asia part of Constantinople. By this way they could be closer the Byzantines. Mehmed II was very strong person. In history pages, they were telling that every night Sultan Mehmed watched Constantinople and dreamed to conquer there. He knew it won't be east to get there.
On 6 April 1453, the Ottomans attacked to Constantinople. They tried to everything to get there. However the Byzantines were defending their city very well. The chains were blocking the ships of the Ottomans, so they couldn't do anything to break their power. Nearly 40 days they stayed around Constantinople. The Byzantines started to lose power, but they were doing everything to defence there. Sultan Mehmed thought everything to get closer their castle, but if he didn't use their ships, they wouldn't conquer there. One night he ordered his soldiers cut some trees. They cut the trees and took tree's body part. They got a lot of big woods. Then Mehmed II ordered them to lubricate the woods. They did it and they stated to push the big fire ships on that oily woods. Maybe you wondered why they did it. The reason was that. They couldn't use the ships because of the chains under the sea. By this way the chains couldn't block them because their this plan.
At the morning the Byzantines couldn't believe that. How did enter the city ? All of them were asking these question. They weren't strong and they were in shock. In a week the city was fall. They accepted to give the city to Ottomans on 29 May 1453. Many Byzantines left the city and they went to Europe. After the victory the Ottomans changed the name of the city. It became Istanbul, which is still using today. They give a nickname to Mehmed II. They started to call him as the "conquerer".
Also the Ottomans made Istanbul as their capital city. Mehmed II gave an order to build there a magnificent castle. They built Topkapi Palace for Sultan Mehmed and his family. Sultan Mehmed meet his dreams. He and his family started to live in Istanbul. After that year nobody can conquer Istanbul, because the Turks love this city.