1840s

The 1840s, spanning 1840 to 1849, was a decade of rapid transformation across politics, society, and technology. It saw the acceleration of industrial capitalism, the expansion of empires, and widespread social upheaval that reshaped many regions of the world.

In Europe, liberal and nationalist movements culminated in the revolutions of 1848, which touched France, the German states, the Austrian Empire, and beyond. Although the immediate outcomes often failed to establish lasting constitutional regimes, the revolutions altered political discourse and accelerated reformist currents. The period also continued the Industrial Revolution’s reach in Britain and continental Europe, with railways, steam navigation, and telegraph networks expanding commercial and social connectivity.

Social crises marked the era as well. The Great Famine in Ireland (1845–1849) caused mass starvation and led to large-scale emigration, transforming Irish demographics and global diaspora patterns. In other parts of the world, empires extended their influence and contested trade practices in Asia and the Americas.

Key global events included the concluding phase of the Opium War (1839–1842), which ended with the Treaty of Nanking and opened Chinese ports while ceding Hong Kong to Britain, signaling new forms of unequal treaties and trade relations. In the Americas, the United States pursued westward expansion: the Texas annexation (1845), the Mexican-American War (1846–1848), and the Treaty of Guadalupe Hidalgo (1848) expanding U.S. territory, followed by the California Gold Rush beginning in 1848. These developments contributed to reshaping national borders, economies, and migratory patterns during the decade.