The Treatise on the Elucidation of the Knowable by the Tibetan master ’Phags-pa, was composed in 1278 as a “manual of Buddhism” for crown prince Zhenjin, second son of the Mongol emperor Qubilai. Translated into Chinese by Ses-rab dpal (Shaluoba) some time before 1306, the text gives descriptions of the animate and inanimate worlds according to Buddhist cosmology in Fascicle One. Fascicle Two offers a précis of basic Buddhist teachings, such as the four truths, dependent origination, and the various factors of the Buddhist path. Contemporary sources likely drawn on by the author, ’Phags-pa, include Vasubandhu’s Abhidharmakosa, the Abhidharmasamuccaya, the Pañcaskandhaka, the Mahayanasutrala?kara, the Prajñapti-sastra, and Prajñaparamita literature. The Cycle of the Formation of the Schismatic Doctrines is based on Xuanzang’s seventh-century Chinese translation (Yibuzonglunlun) of the Samayabhedoparacanacakra, an essay by the ?rst century scholar-monk Vasumitra on the various schismatic doctrines that began to arise soon after the Buddha’s lifetime. The schism of the original Buddhist sangha led to the formation of a number of different Buddhist schools, and the text gives a brief description of each school’s essential tenets and points of doctrine. This important text in Buddhist studies offers insight into the development and doctrines of early Buddhist schools that led eventually to the formation of the Mahayana.