The capital of the Eastern Roman Empire, Constantinople was conquered by the Ottoman Army, under the command Ottoman Sultan Mehmed II on 29th May 1453. With this conquest Ottomans became an Empire and one of the most powerful empires, The Eastern Roman Empire fell and lasted. After the Constantinople conquest, 21 years old Ottoman Sultan II. Mehmed also took the title “The Conqueror” added to his name.

Altough his early age, Sultan II Mehmed, started to prepare siege for İstanbul. He wanted to be the commander as Prophet Hz Muhammed mentioned the conqueror of Constantinople; “One day, Constantinople will be conquered. How wonderful and blessed are the commander of its conquest and his soldiers!” decades ago. First he took precautions with strategic tactics in both inside and outside of the state. After this, he moved to conquer Constantinople.

Constantinople had been an imperial for many years. The city were bombarded by cannon fires which was designed by Mehmed the Second himself. Constantinople had been attacked in the past many times, but its great walls always prevailed. Sultan Mehmed, II changed this with the use of cannons forever. Sultan's massive cannon fired on the walls for weeks.

Baltaoglu Suleyman Bey launched the first attack to enter the Golden Horn gulf on 9th April 1453 and failed to break the chains which was placed at the mouth of the horn. This chain, which floated on wooden logs, was strong enough to prevent any Ottoman ship from entering Golden Horn. The victory of the Pope’s Christian and Genoese ships decreased the morale of the Ottoman army.

During this chaos and widespread feeling of lose, with the Sultan's spiritual menthor Aksemseddin promised certain success about the conquest. Sultan Mehmed improved a new type of cannon as called as “humbara”, today known as “howitzer” which is taken an aim for shooting the target. It is an important discovery for the world’s army history. Cannons were not enough to take the city. Encouraged by spiritual support, Sultan II Mehmed, decided plan for his navy. the Ottoman fleet anchored in Dolmabahce would be moved to the Golden Horn gulf by land as an element of surprise. Several ships and galleys carried by soldiers via rope were slid over slipways. In the morning of 22th April, Eastern Roman Empire woke up with a surprise and terrified when they saw Ottoman galleys in the horn.

On 29th May, the Ottoman army attacked for the final assault. The siege lasted from Friday, 6 April 1453 until 29 May 1453 Tuesday when the city was conquered by the Ottomans under the command of Sultan II. Mehmed. A new era started on the world and a new balance came through by the conquest of Constantinople.