With news of the death of newly re-elected veteran leader Idriss Deby Itno on Tuesday, we look back on the key events of his 30 years at the helm of the huge mostly desert African state.
1990: Seizes the capital
Former army chief turned rebel leader, Deby seizes power in December 1990 when his troops enter the capital N'Djamena and send dictator Hissene Habre fleeing into exile in Senegal.
After six years of transition towards democracy, he is elected president in 1996 in Chad's first multi-party election, bringing some of the political opposition into government.
He is reelected in 2001 but comes under increasing pressure from the opposition accusing him of election fraud and human rights violations.
A 2005 referendum approves changes to the constitution to remove limits on presidential terms.
2008: Rebel offensives
In late 2005 there are mass desertions in army ranks. Soldiers intent on overthrowing the regime set up in the east, near the border with Sudan, where they form armed movements.
In 2006 N'Djamena breaks diplomatic ties with Khartoum for several months, accusing Sudan of aiding rebels who are seeking to overthrow Deby.
In 2008 rebels attack the capital, reaching the gates of the presidential palace before being pushed back with the aid of French forces.
2013: Anti-jihadist fight
Chad deploys 2,000 troops alongside French forces to counter advances by jihadists groups occupying northern Mali since 2012.
In 2014 the French army establishes the headquarters of a new operation against jihadist groups in the region in N'Djamena.
The following year Chad launches a ground offensive in neighbouring Nigeria against the radical Islamist group Boko Haram, which is destabilising the countries bordering Lake Chad.
Chad troops also join the G5 Sahel multinational force headquartered in Mauritania and the 13,000-man UN force in Mali, MINUSMA.
2016: Fifth term
Deby is reelected in April for a fifth mandate with around 60 percent of votes compared to 13 percent for the opposition leader Saleh Kebzabo.
The opposition claims the vote is a "political hold-up".
A month later a special court in Senegal sentences Habre to life in prison for war crimes and crimes against humanity during his time in power in Chad.
In 2018 parliament passes a controversial change to the constitution that further bolsters Deby's powers. The opposition boycotts the vote.
The following year an armed group opposed to Deby -- the Union of Resistance Forces (UFR) led by his nephew Timan Erdimi -- enters Chad in columns of pick-ups.
At N'Djamena's request, France carries out air strikes to stop their advance.
Chad launches another major offensive against Boko Haram in 2020 after the death of around 100 of its soldiers in the Lake Chad area.
2021: Death fighting rebels
In the weeks leading up to the April 11 presidential vote the campaign turns deadly.
In February a gun battle erupts at the home of a candidate after security forces try to arrest him. At least three people die.
Deby, 68, is re-elected to a sixth term after clinching 79.32 percent of the vote, according to provisional results from the electoral commission announced the day before his death.
Hours after the election results are announced, the army says it has killed 300 fighters waging a rebel offensive launched on election day.
On Tuesday the army announces Deby has died of injuries while fighting rebels in the north of the Sahel country.
Deby "has just breathed his last breath defending the sovereign nation on the battlefield," over the weekend, says army spokesman General Azem Bermandoa Agouna in a statement read out on state television.