The history of Arabs in Afghanistan spans over one millennium, from the 11th century Islamic conquest when Arabs arrived with their Islamic mission until recently when others from the Arab world arrived to defend fellow Muslims from the Soviet Union followed by NATO forces. Most of the early Arabs gradually lost their Arabic hegemony and ultimately mixed with the local population, though they are still considered a cognizably distinct ethnic group according to the Constitution of Afghanistan and the Afghan National Anthem. Afghans who carry Sayed or Quraishi in their names usually claim Arab ancestry.