Web15 hours ago · Twelver Shi'ism. Twelver Shīʿism ( Arabic: ٱثْنَا عَشَرِيَّة; ʾIthnā ʿAshariyya ), also known as Imāmiyya ( Arabic: إِمَامِيَّة ), is the largest branch of Shīʿa Islam, comprising about 85% of all Shīʿa Muslims. The term Twelver refers to its adherents' belief in twelve divinely ordained leaders, known as ...