In Tibet, with different geography and customs from central China, and proximity to Nepal and northern India, Buddhism developed a more mysterious and esoteric character. It was, moreover, greatly affected by an influx of tantric masters from northern India who fled to Tibet during the Moslem invasions of the 12th century. Tibet was sparsely populated and vast, so that the teachings of different Buddhist masters began to diverge.
西藏則因為地理風俗迥異於中原，又靠近印度北部和尼泊爾，在十二世紀印度被回族入侵，致佛教在印度滅亡後，許多大師及經典因此而大量傳入西藏，長期發展下來，另成一格，演變為與中原「顯宗」有別的「密宗」教派，又稱為「藏傳佛教」。