Vajrayāna, also known as Esoteric Buddhism, is a form of Buddhism that incorporates tantric practices and rituals to achieve enlightenment. It emerged in India during the 8th century and spread to other parts of Asia, including Tibet, Nepal, Bhutan, and Mongolia. Within Vajrayāna, there are several main schools or lineages that have developed over time.

1. Nyingma The Nyingma school is the oldest of the four major schools of Tibetan Buddhism and is also known as the "Ancient Ones" or "Red Hat" school. It was founded by Padmasambhava, also known as Guru Rinpoche, who is believed to have introduced Vajrayāna teachings to Tibet. The Nyingma tradition emphasizes the importance of oral transmission and the use of mantras, mudras, and visualizations in their practice.

2. Kagyu The Kagyu school is one of the four major schools of Tibetan Buddhism and is known as the "Lineage of Oral Instructions." It was founded by Marpa Lotsawa and his disciple Milarepa in the 11th century. The Kagyu tradition places a strong emphasis on meditation and the use of physical and energetic practices, such as tummo (inner heat) and mahamudra (great seal).

3. Sakya The Sakya school is another major school of Tibetan Buddhism and is known as the "Grey Earth" or "Grey Earth School." It was founded by Khon Konchok Gyalpo in the 11th century. The Sakya tradition places a strong emphasis on the study of Buddhist philosophy and the use of rituals and visualizations to achieve enlightenment.

4. Gelug The Gelug school, also known as the "Yellow Hat" school, is the youngest of the four major schools of Tibetan Buddhism. It was founded by Je Tsongkhapa in the 14th century. The Gelug tradition places a strong emphasis on the study of Buddhist scriptures and the use of logic and reasoning in their practice.

5. Jonang The Jonang school is a smaller school of Tibetan Buddhism that emerged in the 12th century. It was founded by Yumo Mikyo Dorje and places a strong emphasis on the Kalachakra tantra and the concept of shentong (emptiness of other). The Jonang tradition also incorporates elements of the Nyingma and Kagyu traditions.

6. Shangpa Kagyu The Shangpa Kagyu school is a smaller branch of the Kagyu tradition that was founded by Khyungpo Naljor in the 11th century. It emphasizes the practice of Mahamudra and the Six Yogas of Naropa.

7. Bon The Bon tradition is the indigenous religion of Tibet and predates the introduction of Buddhism. However, it has also incorporated many elements of Vajrayāna Buddhism, particularly the Nyingma tradition. The