Henry Preserved Smith and Ignác Goldziher also challenged the reliability of the "hadith", Smith stating that "forgery or invention of traditions began very early" and "many traditions, even if well authenticated to external appearance, bear internal evidence of forgery." Goldziher writes that "European critics hold that only a very small part of the ḥadith can be regarded as an actual record of Islam during the time of Mohammed and his immediate followers." In his "Mohammedan Studies", Goldziher states: "it is not surprising that, among the hotly debated controversial issues of Islam, whether political or doctrinal, there is not one in which the champions of the various views are unable to cite a number of traditions, all equipped with imposing "isnads"".