Vasubandhu (4th century CE) was, according to Mahayana Buddhist tradition, an Indian Buddhist scholar-monk, and along with his half-brother Asanga, one of the main founders of the Indian Yogācāra school. However, some scholars consider Vasubandhu to be two distinct people. Vasubandhu is one of the most influential figures in the entire history of Buddhism. In the Jodo Shinshu branch of Buddhism, he is considered the Second Patriarch. In Zen, he is 21st Patriarch.
Born in Gandhāra in the fourth century, he was at first, or according to other scholars the first Vasubandhu was, a Sarvāstivādin when he initially studied Sarvāstivādin Abhidharma, as presented in the Mahā-vibhāsa. Dissatified with those teachings, he wrote the Abhidharmakośa in verse and his auto-commentary, the Abhidharmakośa-bhāsya, an important summary and critique of the Mahāvibhāsa from the Sautrāntrika viewpoint.
He later converted to Mahāyāna, or according to other scholars the other Vasubandhu was a Mahayanist, and composed many other voluminous treatises, especially on Yogācāra doctrines.