Who was genghis khan? How to spell genghis khan in english

"Чингисхан" на английском пишется как "Genghis Khan". Вот пример использования этого имени в предложении:

"Genghis Khan, born Temüjin, was the founder and first Great Khan of the Mongol Empire, which became the largest contiguous empire in history after his death in 1227."