Original sentence: By the mid-twentieth century, a consensus had emerged among scholars that the historicity of Laozi was doubtful or unprovable and that the Daodejing was "a compilation of Taoist sayings by many hands originating in the 4th century BC
Edited sentence: By the mid-twentieth century, a consensus had emerged among scholars that the historicity of Laozi was doubtful or unprovable and that the Daodejing was "a compilation of Taoist sayings by many hands originating in the -4th century