Starting from Ganden monastery founded by master Tsongkhapa, the Gelug lineage grew into one of the four major Buddhist traditions of Tibet. The teachings and practice of master Tsongkhapa emphasised reliance on logic and reasoning in studying the great Indian treatises, dealing with topics such as valid cognition, the Ornament of Clear Realisations, Middle Way philosophy, Abhidharma, and monastic discipline; a thorough grounding in the sutra teachings based on the Stages of the Path (lam-rim) instructions of master Atisha; and the combined practice of the Vajrabhairava, Guhyasamaja, and Chakrasamvara tantric systems, with an emphasis on Guhyasamaja as the main practice. These formed the distilled essence of the Buddha's vast teachings which master Tsongkhapa considered the most beneficial for the disciples of his time, based on his own learning and spiritual experiences. Being tireless in his compassionate and wise activities, his legacy included a collection of some 210 treatises, and countless disciples throughout Tibet who continued the lineage of blessings that flourishes to this day.
Institutionally, Gelugpas were the dominant tradition in Tibet and Mongolia. The disciples of master Tsongkhapa established numerous monasteries, such as the six major monasteries of the tradition: Ganden, Sera, Drepung (once the world's largest monastery with 10,000 resident monks), Tashi Lhunpo, Labrang, and Kumbum; the Upper and Lower tantric monasteries, Segyu monastery, and many others to preserve and uphold the lineage. After the Tibetan exile, many of these monasteries have been re-established in India.