In the first few years of the 20th century, Lenin argued the case for a democratic and centralised revolutionary party made up of committed activists who could bring socialist politics to workers' struggles.
Lenin's Bolsheviks split with the Mensheviks who wanted a more loosely defined membership.
Lenin built up a relatively stable underground organisation of Bolshevik committees across Russia. The first test for the Bolsheviks was 1905 – a year of mass strikes and revolution.
Russia was convulsed by huge strikes, and the Tsar – Russia's dictator – was shaken by demands for democracy. The working class in St Petersburg, the most important city, formed a soviet, or workers' council.
This was an institution based on directly elected and recallable delegates from each workplace. It was far more representative and democratic than any parliament.
People's ideas were going through massive changes. The young Leon Trotsky, who was Jewish, was elected as president of the soviet, in an extremely antisemitic country.
But the Bolshevik 'committeemen' took an aloof attitude to the movement. They had become Bolsheviks in a period when economic strikes by workers were quite apolitical and revolution seemed to be on the distant horizon.
The new movement didn't fit the Bolsheviks' pre-conceived plan – workers were developing revolutionary ideas, and the soviet mixed economic and political demands.
The Bolsheviks' St Petersburg committee issued an ultimatum to the soviet – 'adopt socialist politics or dissolve immediately'. This was ignored.
Lenin, then in exile, was furious. He saw the massive changes that were taking place: 'The working class has received a momentous lesson in civil war.
'The revolutionary education of the proletariat made more progress in one day than it could have made in months and years of drab, humdrum, wretched existence.'
The Bolsheviks must catch up with a working class that, in the period of mass strikes, was 'instinctively, spontaneously' moving towards the party.
Lenin appealed 'over the heads' of the committeemen to the rank and file Bolsheviks, who he felt were more in touch with the new mood.
He saw that the Bolsheviks would either catch up or become an irrelevance. Lenin argued for the co‑option of large numbers of workers onto the committees and the mass recruitment of activists.
He said, 'All we have to do is to recruit young people more widely and boldly... without fearing them.
'The youth – the students, and still more so the young workers – will decide the issue of the whole struggle. We must, with desperate speed, unite all people with revolutionary initiative and set them to work.'
Although he faced considerable resistance at first, Lenin successfully reoriented the Bolsheviks.
Unfortunately, the 1905 revolution was defeated. But the Bolsheviks' tight membership, disciplined structure and unity in action after internal debate meant that they remained a cohesive force despite this.
With the Tsar's victory, thousands of revolutionaries were imprisoned and many of their networks smashed. A change in the objective situation forced a shift in Bolshevik tactics.
At the height of the revolution, the Tsar had offered to hold elections to a duma, or parliament.
Revolutionaries boycotted it as the Tsar's terms were undemocratic and it seemed his state machine would soon be swept away.
But now the movement had been crushed, and every opportunity to raise the profile of socialist politics had to be seized.
At a joint Menshevik-Bolshevik conference in 1907, Lenin was the only Bolshevik to argue for participation in elections.
Many leading Bolsheviks still clung to the idea that revolution was near and that participation in elections was unnecessary. Lenin won his position inside the Bolsheviks.
Working class confidence began to recover from the defeat of 1905. The Bolsheviks threw themselves into 'every sign of life in the proletariat'.
In 1912 they launched the newspaper Pravda to intervene in the movement. It combined revolutionary politics with reports from workers. Its circulation reached 40,000.
In the years 1905-14 the Bolsheviks changed from being a party of mainly intellectuals trying to lead the workers into a party of politically advanced workers with a significant working class audience.