The Ghaza or Ghazi thesis of Austrian historian Paul Wittek (189(-1978) remained the most powerful theory to explain the rise and expansion of the Ottoman Empire until it began to face severe criticism the 1980s that led it to be largely undermined. Relying on new studies, this paper discusses the soundness of the material and its intellectual foundations and concludes the theory is no longer valid. Two principal reasons are given for why the theory is now obsolete. First, Wittek did not understand the meaning of ghazw (raid, conquest) for the early Ottomans in its proper historical framework, but took it to mean “jihad fi sabil Allah” (holy war) and the spreading of Islam. Second, there are many doubts over Wittek's use of the evidence he relied on to prove his theory found in the chapter on the Ottomans in Ahmedi's Iskandernameh and the inscription on “Shehadet” Mosque in Bursa of 1337. It transpired that Paul Wittek manipulated the evidence he had and that all the intellectual and material foundations he used fail to support his theory. As a consequence, his theory is no longer a valid explanation for the rise of the Ottoman Empire.