The Kingdom of Hanover was a German state that existed from 1814 to 1866. It was established after the Congress of Vienna, which reorganized Europe following the Napoleonic Wars. The kingdom was ruled by the House of Hanover, which also provided monarchs for the United Kingdom until the personal union ended in 1901. In 1866, the Kingdom of Hanover was annexed by the Kingdom of Prussia during the Austro-Prussian War. This marked the end of its independence, and Hanover became part of the larger German Empire when it was formed in 1871. The region is now part of modern-day Lower Saxony in Germany.