1921: Britain concedes defeat in Third British-Afghan War (1919-21). King Amanullah begins modernising reforms.
From 1953: Mohammed Daoud Khan as prime minister under the monarchy builds ties with the USSR and introduces more modernising reforms, especially for women.
1973: Daoud overthrows the monarchy and speeds up reforms.
1978: The PDPA (Afghan Communist Party) overthrows Daoud in a coup and further speeds up measures to transform Afghanistan on the model of the USSR. It is quickly pitched into civil war with a revolt of the countryside under the leadership of landlords and clerics.
1979, December: The USSR invades Afghanistan and takes over the war against the rural revolt.
1989: The USSR, unable to defeat the revolt, withdraws. Rural-based Islamist and warlord groups take most of the country, though PDPA rule in Kabul survives until 1992.
1994-6: The Taliban emerge as a new Islamist militia, recruited from students at Islamic schools in Pakistan, and sweep most of the country, including Kabul. Rival warlords (the Northern Alliance) hold out in the north east until 2001.
2001, September: Al Qaeda people seize planes and crash them into the World Trade Center in New York. The USA demands that the Taliban give up Al Qaeda leader Osama bin Laden from his base in rural Afghanistan, and, when it doesn't, provides air and other support for the Northern Alliance to sweep the Taliban out of power. After much jockeying a new government is formed in Kabul under Hamid Karzai.
2003 onwards: The Taliban expands operations from the bases in Pakistan to which it has retreated. Its activity accelerates in 2006-9.
2009 onwards: US president Obama organises a troop "surge" in Afghanistan to try to drive back the Taliban. By late 2010 he has an "Afghan Good Enough" group working on plans for exit by 2014.
2014: Obama declares the US will withdraw by 2016.
2017: After US misses the 2016 withdrawal date, president Trump announces another, smaller, troop "surge".
2020, February: Trump signs deal with Taliban committing US to withdraw by May 2021.