Afghanistan–Iran relations

Relations between Afghanistan and Iran were officially established in 1935 during Zahir Shah's reign and the Pahlavi dynasty's Reza Shah Pahlavi, though ties between the two countries have existed for millennia. As a result, many Afghans speak Persian, as Dari (an eastern dialect of Persian) is one of the official languages of Afghanistan, and many in Afghanistan also celebrate Nowruz, the Persian New Year.

Source: Wikipedia — Afghanistan–Iran relations (CC BY-SA 4.0)