The title of outlaw was originally issued as a punishment in Roman law and throughout the Middle Ages. As an outlaw, an individual lost all legal protection and could be persecuted or killed at will by other citizens. Furthermore, to provide fire or water - heat or sustenance - to an outlaw was a punishable offence. The Third Reich resurrected the idea of outlawry and it was seriously considered as a punishment for Nazi war criminals.
In popular culture, the idea of the outlaw or bandit has gained romantic and dramatic connotations through the figures of highwaymen, pirates and Robin Hood. In these cases, men have generally chosen to live outside society, often because society itself has done them wrong, and possess an air of mystery and excitement which has inspired poets and writers over several centuries. Outlaws have been cast as romantic heroes, righting wrongs, luring maidens away from their beds and galloping across wild moors in the moonlight.
In Russia, the Cossacks who inhabit the southern steppes were originally exiles and outlaws who came together to form new settlements from around the 14th century. Not all of this terrain then lay within the Russian borders, but as the country expanded its territory the settlers became Russian and fought on behalf of their new country. Some Cossacks also lived in Siberia but would have left their outlaw roots far behind before the Imperial Circus passed through.
The 'brotherhood of free men' described by the outlaw leader points to Communist connections; the party was to lead the Russian Revolution in 1917 and contribute in large part to the first revolution in 1905. This was a wave of political and social unrest, directed partly against the government and partly against undefined oppressors, which spread across the country five years from the time in which the novel is set; it manifested itself in terrorism, strike action, peasant unrest and military mutiny. Although little obvious revolutionary activity had begun prior to the turn of century, the very early twentieth century saw the creation of stronger unions from small groups of outlaws and political dissidents. The men who intercept the circus train would certainly need stronger and more credulous leaders to turn them against the Tsar and Empire.