Here is a recap of the key events since the jihadists declared their "caliphate" in June 2014 to the purported appearance Monday of the group's elusive leader Abu Bakr al-Baghdadi.

- Caliphate -

On June 29, 2014 jihadists of the Islamic State of Iraq and the Levant (ISIL) proclaim a "caliphate" led by Baghdadi across territory seized in Syria and Iraq, re-branding itself the Islamic State (IS).

In Syria, ISIL had in January seized the northern city of Raqa from rebels.

It also seizes a large part of the eastern province of Deir Ezzor, on the border with Iraq, as well as positions in the northern province of Aleppo.

In Iraq, ISIL in June seizes Mosul and Sunni Arab areas bordering the autonomous Kurdistan region in the north.

A badly prepared Iraqi army is routed without a fight.

Raqa and Mosul become the IS's two de-facto capitals.

In July, Baghdadi appears in a video posted on jihadist websites and calls on all Muslims everywhere to "obey" him.

- Atrocities -

In Raqa, the IS carries out beheadings, mass executions, rapes, abductions and ethnic cleansing. It stones to death women suspected of adultery and slaughters homosexuals.

Some of the atrocities are broadcast on video, which the jihadists use as a propaganda tool.

In Iraq, the group seizes the historic home of the Yazidi minority in Sinjar region, turning children into soldiers and using thousands of women as sex slaves.

- Anti-jihadist coalition -

In August 2014, US warplanes strike IS positions in northern Iraq.

Washington then forms a coalition of more than 70 countries to fight the group in both Iraq and Syria. Washington deploys 5,000 soldiers.

- Defeats in Iraq -

In March 2015, Iraq announces the "liberation" of Saddam's hometown of Tikrit, north of Baghdad.

In November, coalition-backed Kurdish forces retake Sinjar.

In 2016, Anbar provincial capital Ramadi is recaptured and Iraqi forces retake Fallujah.

In July 2017, then Iraqi prime minister Haider al-Abadi declares victory in Mosul after a nearly nine-month offensive led by a federal force backed by coalition air strikes.

In August, the last major IS urban stronghold in northern Iraq, Tal Afar, is declared "liberated", as is the whole of Nineveh province.

On December 9, Abadi declares victory in Iraq's three-year war against IS.

- Defeats in Syria -

Backed by US-led air strikes, Kurdish forces in January 2015 drive the jihadists out of the city of Kobane, on the Turkish border.

In August 2016, the US-backed Kurdish-Arab alliance known as the Syrian Democratic Forces (SDF) recaptures Manbij in Aleppo province.

Backed by Turkish tanks and air force, rebels retake Jarabulus, and then, in February 2017, Al-Bab, the last IS bastion in Aleppo province.

In March 2017, Syrian troops backed by Russian jets recapture the ancient desert town of Palmyra.

The oasis city had traded hands several times during the war and become a symbol of the jihadists' destruction of priceless cultural heritage in areas under their control.

In October 2017, the SDF announces the full recapture of Raqa city, capital of the eponymous province.

In September 2018, the coalition launches an offensive against IS pockets in Deir Ezzor province.

On March 23, 2019, the SDF announces the defeat of the "caliphate" after seizing control of Baghouz, IS's final bastion in eastern Syria along the border with Iraq.

- Elusive leader -

For the first time in five years, Baghdadi purportedly appears in a propaganda video released Monday by the jihadist organisation.

The date the footage was filmed is unclear but in the video Baghdadi refers in the past tense to the fight for Baghouz.