The Tartars, or Tatars (the latter is the preferred spelling) are a large Turkic ethnic group from Central Asia. They first appear to have come from the area around Lake Baikal in south-east Siberia in the fifth century AD, although little historical evidence is available to support this. They formed part of the (ethnically unrelated) Mongol invasion of Russia and Europe in the 13th century, which led to the words 'Mongol' and 'Tatar' being used interchangeably. During the period of the Golden Horde, following Genghis Khan's conquests, the Tatar tribes converted to Sunni Islam. As the Golden Horde fell apart, most of the Tatar khanates within it were gradually absorbed into the Russian Empire. It is estimated that the total Tatar population numbered around 10 million at the end of the twentieth century. To this day, Tatar women have a reputation for being fiery tempered and independent.