The Sarvāstivāda school, popular in northwest India and Kashmir, focused on Abhidharma teachings. Their name means "the theory that all exists" which refers to one of their main doctrines, the view that all dharmas exist in the past, present and in the future. This is an eternalist theory of time. Over time, the Sarvāstivādins became divided into various traditions, mainly the Vaibhāṣika (who defended the orthodox "all exists" doctrine in their Abhidharma compendium called the "Mahāvibhāṣa Śāstra"), the Sautrāntika (who rejected the Vaibhāṣika orthodoxy) and the Mūlasarvāstivāda.