Four school

1/ Nyingma school 

The Nyingma school is the oldest of the four major schools of Tibetan Buddhism, founded by followers of Padmasambhava, an Indian tantric master who is believed to have introduced Buddhism to Tibet in the 8th century. The word "Nyingma" means "ancient" in Tibetan, emphasizing its status as the earliest form of Tibetan Buddhism.

Nyingma teachings emphasize the Dzogchen (Great Perfection) tradition, which focuses on the realization of the innate, primordial nature of mind. Dzogchen is considered the highest form of practice, aiming at the direct experience of one's own true nature without relying on complex rituals or intellectual understanding.

2/ kagyu school

The Kagyu school is one of the major schools of Tibetan Buddhism, known for its emphasis on meditation practice and the transmission of esoteric teachings from master to disciple. It is often referred to as the "Oral Lineage" due to the tradition of passing down teachings through direct oral instruction. The Kagyu school traces its origins back to the Indian yogi Tilopa, and through his disciple Naropa, it was brought to Tibet by the renowned translator and master Marpa Lotsawa.

The most prominent lineage within the Kagyu school is the Karma Kagyu, founded by Dusum Khyenpa, who became the first Karmapa. The Karmapas are considered to be the first lineage of reincarnated lamas in Tibet, a tradition that has had significant influence on Tibetan Buddhism.

3/ Sakya school 

The Sakya school is one of the four major schools of Tibetan Buddhism, alongside the Nyingma, Kagyu, and Gelug schools. It was founded in the 11th century by Khon Könchok Gyalpo and is named after the Sakya Monastery in southern Tibet. The word "Sakya" means "pale earth" and refers to the color of the land in the region where the monastery was established.

The Sakya school is known for its emphasis on scholarship and rigorous philosophical training, particularly in the study of logic and epistemology. It follows the teachings of the great Indian scholar and philosopher Nagarjuna, with a focus on the Madhyamaka (Middle Way) view. The Sakya tradition also places great importance on tantric practices and has a specific lineage of Vajrayana teachings.

The leadership of the Sakya school is passed down through the Khon family, making it a unique blend of monastic and hereditary leadership. The head of the Sakya school is traditionally referred to as the Sakya Trizin (Holder of the Sakya Throne). There are two main branches within the Sakya school: the Ngor and the Tsar traditions, both of which emphasize slightly different aspects of the teachings.

The Sakya school has been highly influential in Tibet's religious and political history, especially during the 13th century when the Sakya lamas governed Tibet under the protection of the Mongol Empire.

4/ Gelug school

The Gelug school is one of the major traditions of Tibetan Buddhism, founded by the Tibetan philosopher and monk Je Tsongkhapa (1357–1419). It is sometimes referred to as the "Yellow Hat" school due to the distinctive yellow hats worn by its monks. The Gelug tradition places a strong emphasis on monastic discipline, logic, and philosophical study, particularly based on the works of Indian masters like Nagarjuna and Chandrakirti.