It is hard to say to what extent the Mongols beyond such parts of northern China as felt the direct influence of the imperial court were converted to Lamaism.  At any rate their conversion was only temporary for, as will be related below, a reconversion was necessary in the sixteenth century.  It looks as if the first growth of Mongolian Buddhism was part of a political system and collapsed together with it.  But so long as the Yuan dynasty reigned, Lamaist influence was strong and the downfall of the Yuan was partly caused by their subservience to the clergy and extravagant expenditure on religious buildings and ceremonies.  After the departure of Pagspa, other Lamas held a high position at the Court of Peking such as Chos-kyi-hod-zer and gYun-ston rDo-rje-dpal.  The latter was a distinguished exponent of the Kalacakra system and the teacher of the historian Bu-ston who is said to have arranged the Tibetan Canon.

Although the Yuan dynasty heaped favours upon priests and monasteries, it does not appear that religion flourished in Tibet during the fourteenth century for at the end of that period the grave abuses prevalent provoked the reforming zeal of Tsong-kha-pa.  Prom 1270 to 1340 the abbots of Sakya were rulers of both Church and State, and we hear that in 1320 they burned the rival monastery of Dikung.  The language of Sanang Setsen implies that each abbot was appointed or invested by the Emperor[942] and their power declined with the Yuan dynasty.  Other monasteries increased in importance and a chief known as Phagmodu[943] succeeded, after many years of fighting, in founding a lay dynasty which ruled parts of Tibet until the seventeenth century.

In 1368 the Ming superseded the Yuan.  They were not professed Buddhists to the same extent and they had no preference for Lamaism but they were anxious to maintain good relations with Tibet and to treat it as a friendly but vassal state.  They accorded imperial recognition (with an implication of suzerainty) to the dynasty of Phagmodu and also to the abbots of eight monasteries.  Though they were doubtless glad to see Tibet a divided and contentious house, it does not appear that they interfered actively in its affairs or did more than recognize the status quo.  In the time of Khubilai the primacy of Sakya was a reality:  seventy years later Sakya was only one among several great monasteries.

The advent of the Ming dynasty coincided with the birth of Tsong-kha-pa,[944] the last reformer of Lamaism and organizer of the Church as it at present exists.  The name means the man of the onion-bank, a valley near the monastery of Kumbum in the district of Amdo, which lies on the western frontiers of the Chinese province of Kansu.  He became a monk at the age of seven and from the hair cut off when he received the tonsure is said to have sprung the celebrated tree of Kumbum which bears on its leaves wondrous markings.[945] According to the legend, his birth and infancy were