The ancient history of Afghanistan, also referred to as the pre-Islamic period of Afghanistan, dates back to the prehistoric era and the Helmand civilization around 3300–2350 B.C. Archaeological exploration began in Afghanistan in earnest after World War II and proceeded until the late 1970s during the Soviet–Afghan War. Archaeologists and historians suggest that humans were living in Afghanistan at least 50,000 years ago, and that farming communities of the region were among the earliest in the world. Urbanized culture has existed in the land from between 3000 and 2000 BC. Artifacts typical of the Paleolithic, Mesolithic, Neolithic, Bronze, and Iron ages have been found inside Afghanistan.
After the Indus Valley Civilisation stretched up to northeast Afghanistan, it was inhabited by the Iranic tribes and controlled by the Medes until about 500 BC when Darius the Great (Darius I) marched with his Persian army to make it part of the Achaemenid Empire. In 330 BC, Alexander the Great of Macedonia invaded the land after defeating Darius III of Persia in the Battle of Gaugamela. Much of Afghanistan became part of the Seleucid Empire followed by the Greco-Bactrian Kingdom. Seleucus I Nicator was defeated by Chandragupta Maurya and gave his daughter in a peace treaty. The land was inhabited by various tribes and ruled by many different kingdoms for the next two millennia. Before the arrival of Islam in the 7th century, there were a number of religions practiced in modern-day Afghanistan. Zoroastrianism and Ancient Iranian religions were practiced in western Afganistan (Khorasan and Herat). Hinduism and Buddhism was primarily practiced in regions of Eastern (Kabul) and South-Eastern Afganistan (Kandahar). The Kafiristan (present-day Nuristan) region, in the Hindu Kush mountain range, was not converted until the 19th century. They still follow the ancient Vedic religion (related to modern day Hinduism).
