In an effort bring together Sunnis and Shiites worldwide, Shaltut issued a fatwa (religious injunction). It recognized (Twelver) Shiite law as a fifth school alongside the four Sunni schools. He recognized the Ja'fari school of law (called Ithna Ashariyya, or the Twelvers, the largest group in Shia Islam) as one of the five mainstream schools of thought in Islam. This was an important achievement in attempting to unite Muslims around the world. 