[1] He is responsible for more written responsa to queries posed to him by world Jewry than any of his predecessors, and maintained close contact with the Jews of al-Andalus (now Spain and Portugal).
Questions were addressed to him from all parts of the Jewish diaspora, and his answers, about 300 of which have been preserved in various compilations (e.g., in Sha'are Ẓedeḳ, Teshubot ha-Ge'onim, and Ḳebuẓat ha-Ḥakamim, Tshuvot Rav Natrunai Gaon, Jerusalem 5771, edited by Y. Brody), show his thorough mastery of the subjects treated as well as his ability to impart knowledge.
He endeavored to enforce the observance of every rabbinic provision emanating from or as explained by either of the Talmudic academies in Babylonia.
Since the Karaites rejected the ritualistic forms of these schools, he made strenuous efforts to establish uniformity among the Rabbanites.
Hai ben Sherira, however, denied this, suggesting that some adventurer may have impersonated Natronai and imposed on the Jews of France.