Ernest Augustus, King of Hanover

Born in London on 5 June 1771, Ernest Augustus seemed destined for footnote status as George III's fifth son. Sent to Hanover for military training, he took a disfiguring facial wound fighting Revolutionary France near Tournai. Created Duke of Cumberland in 1799, he married his twice-widowed cousin Frederica in 1815 over his mother's objections - the union proved happy and produced one son, George, in 1819. In the House of Lords he built an extremely conservative record while rumours swirled that he'd murdered his valet, fathered a child by his sister, and plotted to kill Victoria for the British throne. When William IV died in 1837, Salic law sent Ernest to Hanover as its first resident king in over a century. He voided the liberal constitution his predecessor had granted and sacked the Göttingen Seven, including the Brothers Grimm, for protesting. He crushed an 1848 revolution, reluctantly let Hanover join the German customs union in 1850, and died the next year.