Oppostion To Karaites
He staunchly opposed Karaites, Naṭronai endeavored to enforce the observance of every rabbinic provision emanating from or as explained by either of the two great Babylonian academies; and as the Karaites rejected the ritualistic forms of these schools, he made strenuous efforts to establish uniformity among the Rabbinites. Hence the origin of many a ritualistic formula is traced to him (Siddur R. Amram, passim; see also Zunz, Ritus, p. 220).
Naṭronai was also credited with a mastery of transcendentalism. It was said that by this means he caused himself to be mysteriously transported to France, where he instructed the people, and then was as mysteriously transported back to Babylonia. The gaon Hai, however, denied this, suggesting that some adventurer may have impersonated Naṭronai and imposed on the Jews of France (Ṭa'am Zeḳenim, ed. Frankfort-on-the-Main, 1854, pp. 55a, 56a et seq.; comp. A. Harkavy, Zikkaron la-Rishonim wegam la-Aḥaronim, iv., p. xxiii.).
Read more about this topic: Natronai Ben Hilai