While the Provisional Government grappled with foreign foes, the Bolsheviks, who were opposed to bourgeois democracy, gained new strength. Lenin, the Bolshevik leader, returned to Petrograd in April 1917 from his wartime residence in Switzerland. Although he had been born into a noble family, from his youth Lenin espoused the cause of the common workers. A committed revolutionary and pragmatic Marxist thinker, Lenin astounded the Bolsheviks already in Petrograd by his April Theses, boldly calling for the overthrow of the Provisional Government, the transfer of "all power to the soviets," and the expropriation of factories by workers and of land belonging to the church, the nobility, and the gentry by peasants. Lenin's dynamic presence quickly won the other Bolshevik leaders to his position, and the radicalized orientation of the Bolshevik faction attracted new members. Inspired by Lenin's slogans, crowds of workers, soldiers, and sailors took to the streets of Petrograd in July to wrest power from the Provisional Government. But the spontaneity of the "July Days" caught the Bolshevik leaders by surprise, and the Petrograd Soviet, controlled by moderate Mensheviks, refused to take power or enforce Bolshevik demands. After the uprising died down, the Provisional Government outlawed the Bolsheviks and jailed Leon Trotsky (Lev Trotskii, originally Lev Bronstein), an active Bolshevik leader. Lenin fled to Finland.