In 1453, Constantinople—the last bastion of the Byzantine Empire—fell to the Ottomans. Now the Islamic Turks controlled the trade routes to the Far East, including the Silk Road network.
As such, a new gulf sprang up between the European West and the Islamic East.
The trouble was that wealthy Europeans had developed a taste for rare, exotic goods—they needed to find a new way East.
Image: The siege of Constantinople (1453), French miniature by Jean Le Tavernier after 1455.Source: Wiki Commons