Tradition starts the history of the Mahāsāṃghika (Mahāsāńgika/Mahasamghika/Mahasanghika) school of Buddhism with the so-called Buddhist Council of Vaiśālī (present-day Besarh in the northwest of Bihar state), held about a hundred years after the demise of Śākyamuni Buddha. This council is reported to have introduced the first schism in the Buddhist community, when the famous king Aśoka (reigned c. 270–c. 230 BCE) intervened in a dispute among the monastics and decided in favor of the majority, whence the name “Mahāsāṃghika” (“Great Community,” Chinese name “dazhong bu,” 大眾部, as an alternative for the transliteration “Mohesengqi bu,” 摩訶僧祇部). The other group involved in the dispute became known as the Sthaviravādins (“the Elders”), of whom the present-day Theravādins are the only successors…
Although the Mahāsāṃghikas no longer exist as a separate Buddhist school, their doctrinal and cultic developments have been important for the development of the Mahayana, the general name for what was originally known as “bodhisattvayāna.”
Is this an accurate presentation of history, that Theravada originated from a small splinter group from the broader Buddhist community, and that Mahayana eventually developed from the Mahasamghika majority?