Alī ibn Abī Ṭālib was a cousin, son-in-law and companion of the Islamic prophet Muhammad. He ruled as the fourth Rashidun caliph from 656 until his assassination in 661. He is considered one of the central figures in Shia Islam, the first Shia Imam and, in Sunni Islam, as the fourth of the "rightly guided" (rāshidūn) caliphs.

Lionel David Barnett was an English orientalist. He was educated at University College, Liverpool, and Trinity College, Cambridge, where he took a first class degree in classics. In 1899, he joined the British Museum as Assistant Keeper in the Department of Oriental Printed Books and Manuscripts. In 1908 he became Keeper, remaining in the post until his retirement in 1936. He was also Professor of Sanskrit at University College, London, from 1906 to 1917; founding Lecturer in Sanskrit at the School of Oriental Studies (1917–1948); Lecturer in Ancient Indian History and Epigraphy (1922–1948); and Librarian of the School (1940–1947). In 1948, at the age of 77, he rejoined the British Museum, which was desperately short of staff, as an Assistant Keeper, remaining there until his death in 1960.