Since before the latter half of the twentieth century, the 'Book of Giants' had long been known as a 'Middle Iranian' work (which some scholars now believe was written originally in 'Eastern Aramaic') that circulated among the Manichaeans as a composition attributed to Mani ("c". AD 216 – 274) — a Parthian citizen of southern Mesopotamia who appears to have been a follower of Elkesai, a Jewish-Christian prophet and visionary who lived in the early years of the second century. Some scholars, concordant with supporting evidence for the ancient sect's geographical distribution, have posited both genetic and ritual-custom similarities between the Elcesaites and the earlier Second Temple Jewish sect of the Essenes ("Essaioi" 'Saints').