Controversy over whose ideas came first, Janet's or Sigmund Freud's, emerged at the 1913 Congress of Medicine in London. Prior to that date, Freud had freely acknowledged his debt to Janet, particularly in his work with Josef Breuer, writing for example of "the theory of hysterical phenomena first put forward by P. Janet and elaborated by Breuer and myself". He stated further that "we followed his example when we took the splitting of the mind and dissociation of the personality as the centre of our position", but he was also careful to point out where "the difference lies between our view and Janet's".