"ended the king's forty-year reign"

King Mohammed Zahir Shah (1914-2007) came to power in 1933 following the assassination of his father.  For most of his reign, the real power lay with his two uncles, Sardar Mohammad Hashim Khan (Prime Minister 1929-1946) and Sardar Shah Mahmud Khan (Prime Minister 1946-1953).

Zahir Shah
Public DomainZahir Shah - Credit: Voice of America
In 1973, the King was in Italy undergoing eye surgery when Daoud Khan staged a coup d'etat.  He abdicated and remained in exile in Italy for 29 years.  After the 2001 invasion, the US opposed his reinstatement, and instead he was given the ceremonial title "Father of the Nation".  He moved back into the Kabul palace and died there after a long illness.