In recent years, the term "caliphate" has become somewhat warped; it has become more of a slogan for radical Islamist groups than an actual political objective. Even the Islamic State, which has made impressive territorial gains quickly, has only an emirate, which encompasses a far smaller geographic area than a caliphate. Establishing an emirate is not terribly remarkable. Similar groups have established emirates before: The Taliban ruled more than 90 percent of Afghanistan prior to 9/11, and al Qaeda franchise groups oversaw short-lived emirates in Yemen and Mali. Still, the Islamic State's announcement is the first serious attempt at re-establishing the caliphate since the institution was abolished in 1924 by the Turkish republic, which replaced the Ottoman Empire after World War I. Over the past 90 years, there have been a few attempts to revive the caliphate, but none were particularly successful.