Throughout the middle ages the study of logic was pursued but Buddhists and Jains rather than by Brahmans.[240] Vasubandhu composed some treatises dealing exclusively with logic but it was his disciple Diṅnâga who separated it definitely from philosophy and theology. As in idealist philosophy, so in pure logic there was a parallel movement in the Buddhist and Brahmanic schools, but if we may trust the statements of Vâcaspatimiśra (about 1100 A.D.) Diṅnâga interpreted the aphorisms of the Nyâya philosophy in a heterodox or Buddhist sense. This traces the beginnings of Indian logic to a Brahmanic source but subsequently it flourished greatly in the hands of Buddhists, especially Diṅnâga and Dharmakîrti. The former appears to have been a native of Conjevaram and a contemporary of Kâlidâsa. Both the logician and the poet were probably alive in the reign of Kumâragupta (413-455). Diṅnâga spent much time in Nâlanda, and though the Sanskrit originals of his works are lost the Tibetan translations[241] are preserved. The Buddhist schools of logic continued for many centuries. One flourished in Kashmir and another, founded by Candragomin, in Bengal. Both lasted almost until the Mohammedan conquest of the two countries. From about 470 to 530 A.D. northern India groaned under the tyranny of the Huns. Their King Mihiragula is represented as a determined enemy of Buddhism and a systematic destroyer of monasteries. He is said to have been a worshipper of Śiva but his fury was probably inspired less by religious animosity than by love of pillage and slaughter. About 530 A.D. he was defeated by a coalition of Indian princes and died ten years later amid storms and portents which were believed to signify the descent of his wicked soul into hell. It must have been about this time that Bodhidharma left India for he arrived in Canton about 520. According to the Chinese he was the son of a king of a country called Hsiang-Chih in southern India[242] and the twenty-eighth patriarch and he became an important figure in the religion and art of the Far East. But no allusion to him or to any of the Patriarchs after Vasubandhu has been found in Indian literature nor in the works of Hsüan Chuang and I-Ching. The inference is that he was of no importance in India and that his reputation in China was not great before the eighth century: also that the Chinese lists of patriarchs do not represent the traditions of northern India.