The Islamic State's (formerly the Islamic State of Iraq and the Levant) declaration of a caliphate is an attempt to assert itself on other groups, but its demands of allegiance and its vision of returning to a 'purer' era has been greeted by many with derision and rejection.
Fighters loyal to the group's proclaimed "Caliph Ibrahim ibn Awwad", or Abu Bakr al-Baghdadi as he was known until Sunday's announcement, are inspired by the Rashidun caliphate, which succeeded the Prophet Muhammad in the seventh century, and is revered by most Muslims.
Groups like the Islamic State and al-Qaeda believe the lack of a caliphate has contributed to the humiliation they say Muslims have faced in the last century.
The statement published by the Islamic State on Sunday says Muslims "have not tasted honour" since it was lost, and adds that it is "a dream that lives in the depths of every Muslim".
Khaled al-Maeena, the editor-at-large at the Saudi Gazette , told Al Jazeera's Inside Story that the Islamic State's declaration had a "romantic tone".
The armed group was trying to appeal to "people who had been shunned by society" and create a "rallying point", but the fighters will fail in attracting other Muslim groups to their cause, Maeena said.
The Rashidun caliphate has been seen as legitimate by a large number of Muslims, something the Islamic State cannot claim to enjoy. But that has not prevented the group's call for all Muslims to unite under its banner.
The group's declaration is steeped in references to Quranic verses, oral traditions attributed to the Prophet Muhammad, and quotes from classical scholars - a clear attempt to bolster the legitimacy of Baghdadi's claim to be the leader of all Muslims.
Baghdadi's purported descent from the Prophet's grandson is also mentioned to comply with the requirement that a caliph be a member of the Prophet's Quraish tribe.
As well as on its theological grounds, the Islamic State finds clear precedent in the historical conquests of the Rashidun caliphs - rapid military successes against a better-equipped enemy.
In the case of caliphs Abu Bakr, Omar, Othman, and Ali, poorly-armed Arab armies fought and defeated the Byzantine and the Persian empires, bringing about the rapid collapse of the latter.
The Islamic State's declaration recounts the Persian emperor mocking Rashidun soldiers, calling them "miserable" "divided" and "fewer in number", before the Muslim army defeated him at the Battle of Qadisiyyah.
This historical memory is something the Islamic State wants to emulate.
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Azzam Tamimi, an academic who writes on Islamic movements, adds that it is unlikely anyone except "some frustrated youth" would be receptive to Baghdadi’s declaration.
"Such fanatic and desperate movements emerge usually in response to a profound crisis. Yet, their demise is usually rapid because of their tendency to be nihilistic," Tamimi said. They "fail miserably when it comes to winning over the normal and decent", he added.
Since the announcement, some of the major rebel groups in Syria have rejected his call. The Islamic Front, a group fighting both the Islamic State and the Syrian government, describes it as void of legitimacy, divisive, and damaging to their causes.
Hassan Abboud, a leading commander in the armed group, said the announcement was a “conspiracy to divide Syria and Iraq” and weaken Sunni Arabs.
The Islamic State has been shunned by others who share its goal of establishing a caliphate, earning the rebuke of al-Qaeda’s core leadership, including Ayman al-Zawahiri. The al-Qaeda leader has reprimanded fighters loyal to Baghdadi, over their brutal tactics and for fighting rival rebel factions.
The Nusra Front, al-Qaeda's main affiliate in Syria, has been battling the Islamic State since an unsuccessful attempt by Baghdadi to forcibly merge the groups last year. In videos detailing alleged atrocities committed by the Islamic State, the Nusra Front reverses the historic symbolism of the Rashidun era used by their rivals to compare them with a sect that fought against the Rashidun caliph Ali.
By using the word "Khawarij", a reference to religious group which tried to assassinate several companions of the Prophet, the al-Qaeda-linked fighters are directly challenging Baghdadi’s claim to inherit the legacy of the Rashidun caliphate.
Charles Lister, a Visiting Fellow at the Brookings Centre Doha, said the announcement posed a “huge threat” to al-Qaeda and that the group and its affiliates will move to denounce Baghdadi.
There would now be “two competing international jihadist representatives, al-Qaeda, with a now more locally-focused and gradual approach to success; and the Islamic State, with a hunger for rapid results and total hostility for competition,” Lister said.
The Islamic State's declaration leaves no room for those with a foot in both camps. Not one of them has answered the call for allegiance.
Commanding all Muslims to pledge allegiance to the new caliph, the statement says: "it is incumbent upon all Muslims to pledge allegiance to the khalifah Ibrahim and support him"
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Beyond winning its war of legitimacy with al-Qaeda, the Islamic State's fledgling caliphate faces a temporal threat on many fronts.
Aymenn al-Tamimi, a fellow at the Middle East Forum who studies armed groups in Syria and Iraq, said the Islamic State's nationalist allies in Iraq were "almost certainly going to reject" the announcement and "tensions would be increased".
"The Nationalist grouping may work with ISIS (ISIL) in the belief they can get the better of ISIS for control of localities," Tamimi said.
These potential new opponents would add to the Islamic State's existing enemies; the Syrian army, Iraqi government, rival Syrian factions, and possibly Western forces.