The early saṅgha and the first splits
The Buddha’s teachings were preserved orally through councils of senior monks. The First Council compiled the discourses (Sutta) and monastic rules (Vinaya) from memory.
Roughly a century later, disagreements over discipline and doctrine led to a split between the Sthaviravāda (“Teaching of the Elders”) and the Mahāsāṃghika (“Great Assembly”). This was not yet Theravāda versus Mahāyāna. Over time, the early community divided into as many as 18–20 schools.
Why Theravāda stayed close to the earliest texts
Theravāda took root in Sri Lanka after being brought there, tradition holds, by the monk Mahinda during Emperor Aśoka’s reign. Sri Lanka’s relative isolation helped the lineage preserve the Pāli Canon (Tipiṭaka), committed to writing around the 1st century BCE.
The tradition emphasizes fidelity to the historical Buddha’s recorded words and liberation through discipline and insight—the path of the arahant. From Sri Lanka it spread to Myanmar, Thailand, Laos, and Cambodia.
Why Mahāyāna emerged
New scriptures known as the Mahāyāna sūtras began circulating in India. Their authors presented them not as a new religion, but as deeper teachings of the Buddha now ready to be heard.
Mahāyāna made the bodhisattva—one who seeks awakening for all beings—the highest ideal. It also developed the teaching of emptiness (śūnyatā). Thinkers including Nāgārjuna, Asaṅga, and Vasubandhu gave these ideas systematic form.
Traveling along the Silk Road into China, Korea, Japan, and Vietnam, Mahāyāna adapted to local cultures and developed into schools including Pure Land, Chan/Zen, Tiantai/Tendai, and Nichiren.
Why Vajrayāna developed as its own path
Vajrayāna emerged within Indian Mahāyāna as an additional set of methods rather than a doctrinal break. It claimed a faster route to the same bodhisattva goal through tantra: deity visualization, mantra, ritual, symbolism, and direct transmission from a qualified teacher.
It reached Tibet in two main waves from the 7th century onward, producing the Nyingma, Kagyu, Sakya, and Gelug schools. As Buddhism declined in India after the 12th century, Tibet, Bhutan, Mongolia, and the Himalayan region became its principal heartlands.