Stalin married Kato Svanidze in a church ceremony at Senaki in July 1906. In March 1907 she bore a son, Yakov. By that year — according to the historian Robert Service — Stalin had established himself as "Georgia's leading Bolshevik". He attended the Fifth RSDLP Congress, held in London in May–June 1907. After returning to Tiflis, Stalin organised the robbing of a large delivery of money to the Imperial Bank in June 1907. His gang ambushed the armed convoy in Yerevan Square with gunfire and home-made bombs. Around 40 people were killed, but all of his gang escaped alive. After the heist, Stalin settled in Baku with his wife and son. There, Mensheviks confronted Stalin about the robbery and voted to expel him from the RSDLP, but he took no notice of them.