The historiography of Karaism has been highly tendentious. Each historiographical movement since the rise of the Jewish Enlightment has treated it differently. The various representations ranged from an image of " the enemy within`, undermining the validity of Jewish tradition to its acclamation as a rationalistic, enlightened, and national patriotic movement. Sometimes Karaism was also ignored, erased from Jewish memory, or alternately underestimated as an ephemeral historical anecdote. The image of Karaism actually served as a boundary stone delineating various Jewish identities. I intend to use the diverse perceptions of Karaism as a lens through which to examine changing trends in modern Jewish historiography. Special attention will be given to the various attitudes of scholars of the Jerusalem School towards Karaism, mainly those displayed by H.H. Ben Sasson and S.D Goitein.