Passage: The robbery made the Bolsheviks even less popular in Georgia and left the Bolsheviks in Tiflis without effective leadership. After the death by natural causes of his wife Ekaterina Svanidze in November 1907, Stalin rarely returned to Tiflis. Other leading Bolsheviks in Georgia, such as Mikhail Tskhakaya and Filipp Makharadze, were largely absent from Georgia after 1907. Another prominent Tiflis Bolshevik, Stepan Shahumyan, moved to Baku. The Bolsheviks' popularity in Tiflis continued to fall, and by 1911, there were only about 100 Bolsheviks left in the city.The robbery also made the Bolshevik Centre unpopular more widely among European social democrat groups. Lenin's desire to distance himself from the legacy of the robbery may have been one of the sources of the rift between him and Bogdanov and Krasin. Stalin distanced himself from Kamo's gang and never publicized his role in the robbery.

Question: Who died of natural causes?
Ekaterina Svanidze