The 19th (nineteenth) century was a century that began on January 1, 1801, and ended on December 31, 1900. It is often used interchangeably with the 1800s, though the start and end dates differ by a year.
The 19th century saw large amounts of social change; slavery was abolished in the Americas, and the First and Second Industrial Revolutions (which also overlap with the 18th and 20th centuries, respectively) led to massive urbanization and much higher levels of productivity, profit and prosperity. The Islamic gunpowder empires were formally dissolved and European imperialism brought much of South Asia and almost all of Africa under colonial rule.
It was marked by the collapse of the Spanish, Zulu Kingdom, First French, Holy Roman and Mughal empires. This paved the way for the growing influence of the British Empire, the Russian Empire, the United States, the German Empire (essentially replacing the Holy Roman Empire), the Second French Empire, the Kingdom of Italy and Meiji Japan, with the British boasting unchallenged dominance after 1815. After the defeat of the French Empire and its Indian allies in the Napoleonic Wars, the British and Russian empires expanded greatly, becoming the world's leading powers. The Russian Empire expanded in the Caucasus, central and far eastern Asia.
The remaining powers in the Indian subcontinent such as the Kingdom of Mysore and its French allies, Nawabs of Bengal, Maratha Empire, Sikh Empire and the princely states of the Nizam of Hyderabad, suffered a massive decline, and their dissatisfaction with British East India Company's rule led to the Indian Rebellion of 1857, marking its dissolution, however it was later ruled directly by the British Crown through the establishment of the British Raj.
The British Empire grew rapidly in the first half of the century, especially with the expansion of vast territories in Canada, Australia, South Africa and heavily populated India, and in the last two decades of the century in Africa. By the end of the century, the British Empire controlled a fifth of the world's land and one quarter of the world's population. During the post-Napoleonic era, it enforced what became known as the Pax Britannica, which had ushered in unprecedented globalization and economic integration on a massive scale.