As mentioned above, the conversion of the Mongols to Buddhism took place when their capital was at Peking and chiefly affected those resident in China.  But when the Yuan dynasty had been dethroned and the Mongols, driven back into their wilds, were frequently at war with China, they soon relapsed into their original superstitions.  About 1570 Altan[956] Khagan, the powerful chief of the Tumed, became more nearly acquainted with Tibet, since some Lamas captured in a border fray had been taken to his Court.  After causing China much loss and trouble he made an advantageous peace and probably formed the idea (which the Manchus subsequently proved to be reasonable) that if the Mongols were stronger they might repeat the conquests of Khubilai.  The Ming dynasty was clearly decadent and these mysterious priests of Tibet appeared to be on the upward grade.[957] They might help him both to become the undisputed chief of all the Mongol tribes and also to reconquer Peking.  So he sent an embassy to invite the Grand Lama’s presence, and when it was not successful he followed it with a second.

The Grand Lama then accepted and set out on his travels with great pomp.  According to the story he appeared to the astonished Mongols in the guise of Avalokita with four arms (of which two remained folded on his breast) and the imprint of his horse’s hoofs showed the six mystic syllables om mani padme hum.  These wonders are so easily explicable that they may be historical.

A great congregation was held near Lake Kokonor and Sanang Setsen records an interesting speech made there by one of his ancestors respecting the relations of Church and State, which he compared with the sun and moon.  The Lama bestowed on the Khagan high sounding titles and received himself the epithet Dalai or Talai, the Mongol word for sea, signifying metaphorically vast extent and profundity.[958] This is the origin of the name Dalai Lama by which the Tibetan pontiff is commonly known to Europeans.  The hierarchy was divided into four classes parallel to the four ranks of Mongol nobles:  the use of meat was restricted and the custom of killing men and horses at funerals forbidden.  The observance of Buddhist festivals was made compulsory and native idols were destroyed, but the deities which they represented were probably identified with others in the new pantheon.  The Grand Lama specially recommended to the Mongols the worship of the Blue Mahakala, a six armed representation of Siva standing on a figure of Ganesa, and he left with them a priest who was esteemed an incarnation of Manjusri, and for whom a temple and monastery were built in Kuku-khoto.

His Holiness then returned to Tibet, but when Altan Khagan died in 1583 he made a second tour in Mongolia in order to make sure of the allegiance of the new chiefs.  He also received an embassy from the Chinese Emperor Wan-Li, who conferred on him the same titles that Khubilai had given to Pagspa.  The alliance between the Tibetans and Mongols was naturally disquieting to the Ming dynasty and they sought to minimize it by showing extreme civility to the Lamas.