The Kingdom of Afghanistan (Pashto: د افغانستان واکمنان‎, Dǝ Afġānistān wākmanān; Persian: پادشاهي افغانستان, Pādešāhī-ye Afġānistān) was a constitutional monarchy in southern and central Asia established in 1926 as a successor state to the Emirate of Afghanistan. It was proclaimed by its first king, Amanullah Khan, seven years after his accession to the throne.

Amanullah Khan was keen on modernizing the country, resulting in conservative forces causing social upheaval on a number of occasions. When he was visiting Europe in 1927, rebellion broke out again. He abdicated in favour of his brother Inayatullah Khan who only ruled for three days before the leader of the tribal rebellion Habibullah Kalakani took power and reinstated the Emirate.

After 10 months, Amanullah Khan's Minister of War, Mohammed Nadir, returned from exile in India. His British-supported armies sacked Kabul, forcing Habibullah Kalakani to discuss a truce. Instead, Mohammed Nadir's forces apprehended and subsequently executed Kalakani. Mohammed Nadir reinstated the kingdom, was proclaimed King of Afghanistan in October 1929, and went on to revert the reformist path of the last king, Amanullah Khan. He was succeeded by his son, Mohammed Zahir Shah, whose rule started in 1933 and lasted for 39 years. Mohammed Zahir Shah, the last King of Afghanistan, was eventually overthrown by his own cousin Mohammed Daoud Khan who successfully ended the centuries-old monarchy and established a republican Afghan government. It was under the leadership of Zahir Shah that the Afghan government sought relationships with the outside world, most notably with the Soviet Union, United Kingdom and the United States.

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