An explosion rocks the Syrian city Kobani during a reported suicide car bomb attack by the Islamic State (ISIS) group on a People's Protection Unit (YPG) position in the city center, as seen from the outskirts of Suruc, on the Turkey-Syria border, October 20, 2014. Gokhan Sahin/Getty Images

When Abu Bakr al-Baghdadi took the podium at a mosque last June to deliver his first public Friday sermon, the world got a glimpse of the man who led an obscure extremist group from Syria to storm across the border into Iraq and took over the second-largest city in that nation to establish itself as the most serious menace to the existing order in the Middle East. Three weeks earlier, on June 10, the Islamic State group had easily routed the Iraqi army from Mosul. Now Baghdadi, wearing a black robe and turban, was announcing the creation of a caliphate that knew no modern borders and proclaiming himself its leader.

Soon after Baghdadi’s speech, pledges of allegiance to the group -- also known as ISIS -- poured in from individuals, small independent jihadist organizations and large groups whose allegiance used to be to al Qaeda, of which Baghdadi himself was formerly a member. One year later, despite an American-led air campaign to eradicate it, the Sunni extremist group has an operational presence in 10 countries, its eye on several others and a wide recruiting network, as well as a reputation for unparalleled brutality.

“ISIS is the crack cocaine of violent extremism, all of the elements that make it so alluring and addictive purified into a crystallized form,” Jessica Stein and J.M. Berger wrote in “ISIS: State Of Terror.”

Though ISIS supporters now span the globe, ISIS has official provinces, also known as "wilayat," only in places where it can directly exert a form of control. The expansion of the so-called caliphate happens according to a clear procedure. Each current and future wilāyah (the singular form of the word) has its own a strategic purpose for the group, whose stated goal is widespread domination according to the strictest interpretation of Shariah, or Islamic law. The application process is complicated and long. Several groups that pledged allegiance to Baghdadi in the early months of the caliphate have yet to be acknowledged as provinces.

“The policy of the Islamic State is known,” according to ISIS online magazine Dabiq. “It does not give any person or group permission to announce a wilāyah or present themselves as officials representing the Islamic State leadership until the aforementioned process has concluded.”

Before announcing their allegiance to ISIS, extremist groups that aspire to lead a wilāyah must have a unified leadership, a strong base of fighters and be the dominant jihadi group in the area. Each hopeful “state” must agree on who will take on a leadership role.

Last November, Baghdadi surfaced again, this time in an audio recording released by the official ISIS media house. He accepted the allegiance of the first wilāyah outside of Iraq and Syria, announcing the expansion of the so-called caliphate to Yemen, Saudi Arabia, Algeria, Libya and Egypt’s Sinai Peninsula. In January, ISIS created In January, ISIS created Wilāyah Khorasan, which spans parts of Pakistan and Afghanistan.

“In some ways the announcement was the debut of the first ISIS affiliates,” Berger and Stein wrote. “But more accurately it appeared to be an expansion of the proto-state itself beyond contiguous borders.”

Once the groundwork has been done, the next step to getting Baghdadi’s acceptance is to publicly declare allegiance in a way that can be documented and shared. Some groups, like Algeria’s Jund al-Khilafa, chose to prove their loyalty by making a brutal ISIS-style execution video. Others, like the Shura Youth Council in Libya -- which controls the city of Derna -- held pro-ISIS rallies in the streets. The rallies were videotaped and photographed so they could be distributed over various social media platforms.

ISIS fighters train at a camp in Benghazi, Libya, in May 2015. Media Office Wilayat Barqa/Islamic State group

The underlying goal is for Baghdadi to be recognized as the leader who can restore the Muslim world to the perceived glories of the past.

“It is necessary that bayah (allegiance) becomes so common to the average Muslim that he considers those holding back as grossly abnormal,” according to the second issue of ISIS magazine Dabiq. “This effort, God willing, will encourage Islamic groups to abandon their partisanship and also announce their bayah to the Khalifa Ibrahim [Baghdadi.]”

The ISIS wilayat differ from the al Qaeda system used in the past, in which groups would operate alongside al Qaeda’s core organization to help it achieve its goal of attacking the West. An ISIS wilāyah operates with the reinforcement of ISIS leadership and the notoriety of the ISIS brand to seize territory, conduct attacks, recruit and govern in its home country as part of a mission to solidify the caliphate’s expansion.

isis khorasan
Sheikh Abu Omar Maqbool, a former spokesman for the Pakistani Taliban, pledges allegiance to the Islamic State group in this still from a video released by an ISIS media wing Jan. 26, 2015. Khurasan Media/The Islamic State

“ISIS is choosing groups that are already active in conflict zones and helping them to gain power and perhaps territorial control more easily,” Harleen Gambhir, counterterrorism analyst at the Institute for the Study of War, recently told International Business Times. “It’s more a matter of ISIS tailoring its strategy within each wilāyah to whatever the regional fight is, to help their affiliates have the most power.”

The degree of coordination between ISIS leadership in Iraq and Syria varies according to ISIS’ needs and the resources available locally. One “state” may serve to give ISIS a foothold in an area where it has been less active, while ISIS may be able to actually seize and govern territory in another. ISIS has claimed to be in direct contact with the wilayat leaders and “is likely funneling strategic resources and military training to its most robust wilayat,” according to the Institute for the Study of War.

The first group to become an official ISIS wilāyah was Ansar Bait al-Maqdis, based in the Sinai Peninsula. After Baghdadi acknowledged its pledge of allegiance, the group’s media campaign and propaganda significantly improved, as did the intensity of its attacks on Egyptian security forces, which signals an influx of ISIS resources to the group.

“The Islamic State has chosen wisely in terms of establishing new provinces or states,” according to a report from the Soufan Group. “The group might lose cities, even hugely important ones such as Mosul or, one day, Raqqa, but its wilayat will likely remain and then try to expand once more.”