A violent earthquake struck the Caucasus near Ganja, killing up to an estimated 300,000 people. 1139 Ganja earthquake: The 1139 Ganja earthquake was one of the worst seismic events in history. It affected the Seljuk Empire and the Kingdom of Georgia, in modern-day Azerbaijan and Georgia. The earthquake had an estimated magnitude of 7.0–7.3 Mw, 7.5 Ms, and 7.7 MLH. A disputed death toll of 230,000–300,000 resulted from this event, making it one of the deadliest earthquakes ever recorded. September 30, 1139. Wiki link