The Collapse of the Byzantine Empire was the final attack of the capital of the Byzantine Empire. On May 29, 1453, the Ottoman Empire held a massive siege on Constantinople.
The destruction of Constantinople was the end of the Roman Empire, which was a huge empire built over 2,000 years earlier. After the conquest, the Ottoman Emperor transferred the capital of the Ottoman Empire from Adrianople to Constantinople. He rebuilt the city to be Ottoman, and renamed it Istanbul.
The end of the Byzantine Empire was a huge blow to the rest of Europe. It ended the renaissance in that region, and started the beginning of the end of the renaissance in the rest of Europe.