In the mid-20th century, the scholar Nabia Abbott found a document with a few lines of an Arabic work with the title "The Book of the Tale of a Thousand Nights", dating from the 9th century. This is the earliest known surviving fragment of the "Nights". The first reference to the Arabic version under its full title "The One Thousand and One Nights" appears in Cairo in the 12th century. Professor Dwight Reynolds describes the subsequent transformations of the Arabic version: