The modern country containing Otrar, where Genghis Khan's envoys were killed, is Kazakhstan. Otrar—also known as Otyrar or Farab—stood near the Syr Darya River in a fertile oasis of southern Kazakhstan and became an important Silk Road center.
In 1218, Genghis Khan sent a large trade caravan and diplomatic mission toward the Khwarezmian Empire. The governor of Otrar, Inalchuq, accused the visitors of espionage and had them detained; most accounts say they were killed or executed. When Genghis Khan demanded justice and compensation, the Khwarezmian ruler Muhammad II failed to resolve the crisis.
The incident became the immediate trigger for the Mongol invasion of the Khwarezmian Empire. Otrar was besieged by Mongol forces and fell in 1220 after a prolonged defense. It was later rebuilt, but centuries of warfare and the decline of Silk Road trade eventually left the settlement abandoned. The ruins are now an important archaeological site in Kazakhstan.