Alexei, the only son of Nicholas II and heir to the Russian throne, had hemophilia. A man named Rasputin claimed he could cure Alexei through his mystical powers, gaining influence over the royal family. Rasputin's opposition to reforms and support of autocracy made him unpopular. In 1917, food shortages and unrest led to the overthrow of Nicholas II and the establishment of a provisional government, but the Soviets gained power and Lenin returned to Russia. In November 1917 the Bolsheviks seized power in the Bolshevik Revolution, establishing the Soviet Union with Lenin as its leader.