But Tibet was fragmented under the influence of its various sects and subsects , which attracted Mongol invasion .
One of the Guge brothers , Chang chub - O , had even got the Tabo Monastery in Spiti refurbished .
Tibet was fragmented under the influence of its various sects and subsects , which attracted Mongol invasion .
One of the Guge brothers , Chang chub - O , had even got the Tabo Monastery in Spiti refurbished .