The fall of Constantinople in 1453 effectively ended what was left of the Roman Empire and set a major roadblock to trade between Europe and the Far East. Additionally, for centuries the city had held back Muslim invaders from the Middle East from invading Europe.
When Sultan Mehmed II and the Turks captured Constantinople in 1453, they changed the name to Islambol, meaning "City of Islam." The famed Hagia Sophia church was converted into a mosque, and much of the city's Christian monuments and heritage was destroyed.
With the city under Turkish control, it became increasingly dangerous and almost impossible for Christian traders to travel the Far East by land. Portugal and Spain took this opportunity to set about sending sailing expeditions around Africa to find a path to India by waterway. This indirectly led to some expeditions sailing too far west and discovering South America and North America, opening up a new age of discovery and colonization.
With the city under Muslim control, Muslim leaders were able to organize military campaigns in Europe. Additionally, the Turks solidified their own powerful empire, the Ottoman Empire, which controlled much of the Middle East for over 450 years until its defeat and collapse during World War I.