 The death of a son (1330) interrupted his work for a time, but he soon took it up again.In 1346 he wrote his "Sefer ha-Mora," a refutation of the philosophical views on the Creation.Believing that he had placed Rabbinism on a sure foundation, Shemariah undertook, in 1352, a journey to Castile and Andalusia, in order to convert the Karaites.