The world's most-wanted man has been rumoured wounded or killed a number of times in the past, and while he was said to have left Mosul earlier this year , his whereabouts were never confirmed.

The 46-year-old Iraqi-born leader of the IS, nicknamed "The Ghost", has not been seen in public since his 2014 visit to the mosque, and the fortunes of his "caliphate" have since made a drastic turn for the worse.

That appearance made the mosque a symbol of IS rule, and the jihadists did not allow it to be captured intact, blowing it and its famed leaning minaret up in June as Iraqi forces closed in.

The reclusive jihadist chief made his only known public appearance as "caliph" at Friday prayers at the Grand Mosque of al-Nuri in Mosul, where on Sunday Iraq declared victory over Baghdadi's Islamic State group after a gruelling battle.

Discreet in his youth and invisible as the world's most wanted man, Abu Bakr al-Baghdadi rose through the ranks quietly and patiently to become global jihad's undisputed supremo.

Introvert

His low profile -- a perfect antithesis to Osama bin Laden -- is partly what Baghdadi, who has a $25-million US bounty on his head, has owed his rise as well as his survival to.

(FILES) This image grab taken from a propaganda video released on July 5, 2014 allegedly shows the leader of the Islamic State jihadist group, Abu Bakr al-Baghdadi (photo by: -/AL-FURQAN MEDIA/AFP/File)

The man who in 2014 became the overlord of a jihadist state ruling over millions of inhabitants was born Ibrahim Awad al-Badri to a modest family in Samarra, north of Baghdad.

Baghdadi's high school results were too modest to undertake a law degree and his

eyesight too bad to join the army so he moved to the capital to study Islam, settling in the neighbourhood of Tobchi.

After US-led forces invaded Iraq in 2003, he founded his own insurgent outfit.

It never carried out major attacks, however, and by the time he was arrested in February 2004 and detained at the Camp Bucca facility, he was still very much a second or third-tier jihadist.

Strategist

The US prison in southern Iraq, which was later dubbed "the University of Jihad", was where he started showing signs of the leader he is now.

He was released at the end of 2004 for lack of evidence. Iraqi security services arrested him twice subsequently, in 2007 and 2012, but let him go because they did not know who he was.

In 2005, he pledged allegiance to Abu Musab al-Zarqawi, the brutal leader of one of IS's many previous incarnations.

Zarqawi was killed in 2006 and Baghdadi took over from his successor, who was also eliminated, in 2010.

He revived the fortunes of Iraq's struggling Al-Qaeda affiliate, the Islamic State of Iraq (ISI), turning it into the independent IS group, expanding into Syria in 2013 and then launching its sweeping offensive in Iraq in 2014.

Baghdadi grew up in a family divided between a religious clan and another of officers loyal to Saddam Hussein's secular Baath party.

Rapist

Years later, his masterstroke as a jihadist leader was arguably to incorporate the ex-Baathists his predecessors had either fought or ignored into his organisation.

It gave his leadership the military legitimacy he personally lacked and formed a solid backbone for the future IS group, whose extremist religious propaganda was combined with formidable guerrilla efficiency.

Uncharismatic and an average orator, Baghdadi was described by his repudiated ex-wife Saja al-Dulaimi, who now lives in Lebanon, as a "normal family man" who was good with children.

Baghdadi is thought to have had three wives, Asma al-Kubaysi, Isra al-Qaysi -- from

Iraq and Syria -- and another, more recent, from the Gulf.

He has also been accused of having repeatedly raped girls and women he kept as sex slaves, including a pre-teen Yazidi girl and the US aid worker Kayla Mueller who was subsequently killed.