Reasons:
Explanation:
When The Ottoman Empire started to crumble, Tsar Nicholas I of Russia referred to the Empire as a "very sick man" in 1853, after that the nickname of the Ottoman Empire spread through the entire world.
The Ottoman Empire was facing a big diversity of ethnic and religious groups that started forming their own countries and where not friendly with each other, and their army was not strong enough to control those groups. The Ottoman Empire survived because France and Britain defended them so that Russia would not take over the Empire, not because of their government who was not able to support their population.