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A chronology of key events:
1500s - Ottomans absorb part of Yemen into their empire but are expelled in the 1600s.
1839 - Aden comes under British rule, and when the Suez Canal opens in 1869 serves as a major refuelling port.
1849 - Ottomans return to north, but later face revolt.
1918 - Ottoman empire dissolves, North Yemen gains independence and is ruled by Imam Yahya.
1948 - Yahya assassinated, but his son Ahmad beats off opponents of feudal rule and succeeds his father.
1962 - Imam Ahmad dies, succeeded by his son but army officers seize power, set up the Yemen Arab Republic, sparking civil war between royalists supported by Saudi Arabia and republicans backed by Egypt.
South Yemen formed
1967 - Formation of People's Republic of Yemen, comprising Aden and former Protectorate of South Arabia.
1969 - Marxists take power in south, rename state People's Democratic Republic of Yemen and reorient economy, society and foreign policy towards Soviet bloc.
1971 - Thousands flee to north following crackdown on dissidents. Armed groups formed in bid to overthrow government.
1972 - Border clashes between two Yemens, ceasefire brokered by Arab League.
1978 - Ali Abdallah Saleh becomes president of North Yemen.
1979 - Fresh fighting between two Yemens. Renewed efforts to unite the two states.
1982 - Earthquake kills 3,000.
1986 - Thousands die in south in political rivalry. President Ali Nasser Muhammad flees the country and is later sentenced to death for treason. New government formed.
North and south unite
1990 May - Two Yemens united as Republic of Yemen with Mr Saleh as president, as Soviet bloc implodes. Tension between former states endures.
1992 - Food price riots in major towns.
1993 April - Coalition government formed, made up of ruling parties of former north and south.
1993 August - Vice-President Ali Salim al-Baid withdraws to Aden, alleging that south is being marginalised and southerners are being attacked by northerners.
1994 May - Saleh declares state of emergency and dismisses al-Baid and other southern government members following political deadlock and sporadic fighting. Former armies that failed to integrate square off on old border.
1994 May-July - Al-Baid declares independence of Democratic Republic of Yemen. Northern forces capture Aden, southern leaders flee abroad and are sentenced to death in absentia.
1995 - Yemen, Eritrea clash over disputed islands in Red Sea.
2000 October - US naval vessel USS Cole damaged in al-Qaeda suicide attack in Aden. Seventeen US personnel killed.
2001 February - Violence in run-up to disputed municipal polls and referendum, which back extension to presidential term and powers.
2002 February - Yemen expels more than 100 foreign Islamic clerics in crackdown on al-Qaeda.
2002 October - Al-Qaeda attacks and badly damages oil supertanker MV Limburg in Gulf of Aden ,killing one and injuring 12 crew members and costing Yemen dear in lost port revenues.
2003 April - The 10 chief suspects in the bombing of the USS Cole escape from custody in Aden. Two are re-captured in 2004.
2004 June-August - Hundreds die as troops battle Shia insurgency led by Hussein al-Houthi in the north.
2004 August - Court sentences 15 men on terror charges, including bombing of Limburg tanker in 2002.
2004 September - Government says its forces have killed dissident cleric Hussein al-Houthi, the leader of a revolt in the north.
2005 March-April - More than 200 people are killed in a resurgence of fighting between government forces and supporters of the slain rebel cleric Hussein al-Houthi.
2005 May - President Saleh says the leader of the rebellion in the north has agreed to renounce the campaign in return for a pardon. Minor clashes continue.
2005 July - Police and witnesses say at least 36 people are killed across the country in clashes between police and demonstrators protesting about a cut in fuel subsidies.
2005 December - More than 60 people are killed when a landslide destroys a mountain village around 20km from Sanaa.
2006 March - More than 600 followers of slain Shia cleric Hussein al-Houthi who were captured following a rebellion he led in 2004 are released under an amnesty.
2006 September - President Saleh wins another term in elections.
2007 January-March - Scores are killed or wounded in clashes between security forces and al-Houthi rebels in the north.
2007 June - Rebel leader Abdul-Malik al-Houthi accepts a ceasefire.
2007 July - Suicide bomber attacks a tourist convoy killing eight Spaniards and two Yemenis in the province of Marib.
2007 August - Citizens banned from carrying firearms in Sanaa. Demonstrations without a permit are outlawed.
2007 October - Volcano erupts on the Red Sea island of Jabal al-Tair where Yemen has a military base.
2007 November - Clashes between Yemeni tribesmen and army personnel protecting a Ukrainian oil company leave 16 people dead in the south-eastern Shabwa province.
2008 January - Renewed clashes between security forces and rebels loyal to Abdul-Malik al-Houthi.
2008 April - Clashes with troops as southern Yemenis protest against alleged northern bias in state job allocation. One man killed.
2008 March-April - Series of bomb attacks on police, official, diplomatic, foreign business and tourism targets. US embassy evacuates all non-essential personnel.
2008 September - Attack on US embassy in Yemeni capital Sana'a kills 18 people, including six assailants. Six suspects arrested.
2008 October - President Saleh announces arrest of suspected Islamist militants allegedly linked to Israeli intelligence.
Demands for reform
2008 November - Police fire warning shots at Common Forum opposition rally in Sanaa. Demonstrators demand electoral reform and fresh polls. At least five protesters and two police officers injured.
2009 February - Government announces release of 176 al-Qaeda suspects on condition of good behaviour.
2009 August - The Yemeni army launches a fresh offensive against Shia rebels in the northern Saada province. Tens of thousands of people are displaced by the fighting.
2009 November - Saudi Arabia says it has regained control of territory seized by Yemeni rebels in a cross-border incursion.
2009 December - Yemen-based branch of al-Qaeda claims it was behind failed attack on US airliner. The government calls on the West for more support to help it combat the al-Qaeda threat.
2010 February - Government signs ceasefire with Houthi northern rebels, which breaks down in December.
2010 September - Thousands flee government offensive against separatists in southern Shabwa province.
2010 October - Global terror alert after packages containing explosives originating in Yemen are intercepted on cargo planes bound for the US.
2011 January - Tunisian street protests encourage similar demonstrations in other countries, including Yemen. President Saleh pledges not to extend his presidency in 2013 or to hand over to his son.
2011 June - After months of mounting protests, President Saleh is injured in rocket attack and flown to Saudi Arabia, returning home in September.
2011 September - US-born al-Qaeda leader Anwar al-Awlaki is assassinated by US forces.
Unity government, growing violence
2011 November - President Saleh agrees to hand over power to his deputy, Abdrabbuh Mansour Hadi. Unity government including prime minister from opposition formed.
2012 February - Abdrabbuh Mansour Hadi inaugurated as president after uncontested elections.
2012 September - Defence Minister Muhammad Nasir Ahmad survives car bomb attack in Sanaa that kills 11 people, a day after local al-Qaeda deputy head Said al-Shihri is reportedly dead in the south.
2012 November - A Saudi diplomat and his bodyguard are shot dead in Sanaa. Security officials say the assailants, who opened fire on the diplomat's convoy, were dressed in police uniforms.
2014 January - National Dialogue Conference winds up after ten months of deliberation, agreeing a document on which the new constitution will be based.
2014 February - Presidential panel gives approval for Yemen to become a federation of six regions as part of its political transition.
2014 July - Tribesmen blow up the country's largest oil pipeline, disrupting supplies from the interior to a Red Sea export terminal.
2014 August - President Hadi sacks his cabinet and overturns a controversial fuel price rise following two weeks of anti-government protests in which Houthi rebels are heavily involved.
2014 September - Houthi rebels take control of the most of capital Sanaa.
2015 January - Houthis reject draft constitution proposed by government.
2015 February - Houthis appoint presidential council to replace President Hadi, who flees to Aden southern stronghold.
2015 March - Islamic State carries out its first major attacks in Yemen - two suicide bombings targeting Shia mosques in Sanaa in which 137 people are killed.
Houthi rebels start to advance towards southern Yemen. President Hadi flees Aden.
Saudi-led coalition of Gulf Arab states launches air strikes against Houthi targets and imposes naval blockade.
2015 June - Leader of Al-Qaeda in Arabian Peninsula, Nasser al-Wuhayshi, killed in US drone strike in Yemen.
2015 September - President Hadi returns to Aden after Saudi-backed government forces recapture the port city from Houthi forces and launch advance on Aden.
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