IV. [The First Two Councils]

Following the Buddha’s Parinibbāna, the First Council was held at Rājagaha to preserve the Dhamma and Vinaya against corruption. Five hundred Arahants, led by Mahākassapa, codified the teachings. One hundred years later, the Second Council convened at Vesālī to suppress the ten unlawful practices of the Vajjian monks. These assemblies ensured the purity of the doctrine and led to the formal establishment of the Theravāda tradition against emerging sectarian schisms.