Khalidi argues that the modern national identity of Palestinians has its roots in nationalist discourses that emerged among the peoples of the Ottoman empire in the late 19th century that sharpened following the demarcation of modern nation-state boundaries in the Middle East after World War I. Khalidi also states that although the challenge posed by Zionism played a role in shaping this identity, that "it is a serious mistake to suggest that Palestinian identity emerged mainly as a response to Zionism."