development Index, and fares much worse in terms of per-capita GDP (PPP), ranking 169th out of 186 countries . Etymology Some scholars suggest that the root name Afghān is derived from the Sanskrit word Aśvakan, which was the name used for ancient inhabitants of the Hindu Kush. Aśvakan literally means "horsemen", "horse breeders", or "cavalrymen" (from aśva, the Sanskrit and Avestan words for "horse"). However, others such as Ibrahim Khan have contended that the word Afghan comes from Bactrian. Historically, the ethnonym Afghān was used to refer to ethnic Pashtuns. The Arabic and Persian form of the name, Afġān, was first attested in the 10th-century geography book Hudud al-'Alam. The last part of the name, "-stan", is a Persian suffix meaning "place of". Therefore, "Afghanistan" translates to "land of the Afghans", or "land of the Pashtuns" in a historical sense. According to the third edition of the Encyclopedia of Islam: The term "Afghanistan" first appeared in 1855, during the reign of Dost Mohammad Khan. Ancient history Many empires and kingdoms have also risen to power in Afghanistan, such as the Greco-Bactrians, Indo-Scythians, Kushans, Kidarites, Hephthalites, Alkhons, Nezaks, Zunbils, Turk Shahis, Hindu Shahis, Lawiks, Saffarids, Samanids, Ghaznavids, Ghurids, Khaljis, Kartids, Lodis, Surs, Mughals, and finally, the Hotak and Durrani dynasties, which marked the political origins of the modern state. Throughout millennia several cities within the modern day Afghanistan served as capitals of various empires, namely, Bactra (Balkh), Alexandria on the Oxus (Ai-Khanoum), Kapisi, Sigal, Kabul, Kunduz, Zaranj, Firozkoh, Herat, Ghazna (Ghazni), Binban (Bamyan), and Kandahar. The country has been home to various peoples through the ages, among them the ancient Iranian peoples who established the dominant role of Indo-Iranian languages in the region. At multiple points, the land has been incorporated within vast regional empires; among them the Achaemenid Empire, the Macedonian Empire, the Maurya Empire, and the Islamic Empire. For its success in resisting foreign occupation during the 19th and 20th centuries, Afghanistan has been called the "graveyard of empires", though it is unknown who coined the phrase. Prehistory and antiquity Excavations of prehistoric sites suggest that humans were living in what is now Afghanistan at least 50,000 years ago, and that farming communities in the area were among the earliest in the world. An important site of early historical activities, many believe that Afghanistan compares to Egypt in terms of the historical value of its archaeological sites. Ancient era