Closer contacts ensued when the Mongols successively sought to move through the Sino-Tibetan borderlands to attack the Jin dynasty and then the Southern Song, with incursions on outlying areas. One traditional Tibetan account claims that there was a plot to invade Tibet by Genghis Khan in 1206,[30] which is considered anachronistic; there is no evidence of Mongol-Tibetan encounters prior to the military campaign in 1240.[31] The mistake may have arisen from Genghis' real campaign against the Tangut Xixia.[31][32]