Timeline Story so far
1990: Unification of north and south Yemen to form a single state under president Ali Abdullah Saleh (pictured).
2003-09: Houthi group in north violently protests marginalisation of the local Shia Zaydi Muslim sect.
2011: Arab Spring protests undermine Saleh’s rule. 2012: Saleh steps down in transition plan backed by Gulf states. Abd-Rabbu Mansour Hadi becomes interim president. 2013: Saleh and his allies undermine the political transition. 2014: The Houthis advance south from Saada and seize Sanaa with help from Saleh. 2015: Hadi tries to announce a new federal constitution opposed by the Houthis and Saleh, who arrest him. He escapes, pursued by the Houthis, triggering Saudi intervention. Saudi-led coalition drives the Houthis and Saleh loyalists from Aden in south Yemen and Marib, northeast of Sanaa, but the front lines solidify, setting up years of stalemate. 2016: Coalition air strikes that kill civilians prompt warnings from rights groups, but western support for military campaign continues. 2017: Saleh switches sides, but is killed trying to escape his former Houthi allies. 2018: Coalition-backed forces advance up the Red Sea coast against the Houthis, aiming to take the port of Hodeidah, the last main entry point for supplies into north Yemen. – Reuters