 Patricia Crone, from the Revisionist school of Islamic studies on the other hand, writes that "the plain truth is that the name Macoraba has nothing to do with that of Mecca [...] if Ptolemy mentions Mecca at all, he calls it Moka, a town in Arabia Petraea" (in northwest Arabia near present-day Petra).The first direct reference to Makkah in external literature occurs in 741 CE, in the Byzantine-Arab Chronicle, though here the author places it in Mesopotamia rather than the Hejaz.Given the inhospitable environment, and lack of historical references in Roman, Persian and Indian sources, historians including Patricia Crone and Tom Holland have cast doubt on the claim that Mecca was a major historical trading outpost.