The Iraqi Government claimed to have killed Nasser - whose real name is Neaman Salman Mansour al-Zaidi - in February 2011. But, it is believed he survived the attack and remains a close adviser to Abu Bakr al-Baghdadi, the current head of Isis.
The Zarqawi group had also envisaged the capture of Iraqi government military bases to seize weapons for use against the enemy. In Syria, one of the major operations carried out by Isis was the seizure of Menagh airbase, near Aleppo, in the summer of 2013. The attack was carried out in conjunction with the Free Syrian Army before the two groups began fighting each other in an attritional civil war.
In the east of the country, Isis seized oilfields, expelling other rebel groups in the area; it even, after a while, began selling some of the oil back to the regime.
In Iraq, Isis gained significant stockpiles of arms, as well as millions of dollars from the banks, after overrunning Mosul last week. Even if its forces are pushed out of the city in the future, the loot will be massively useful in Iraq as well as in Syria. It is also in a position to control oilfields, although it is improbable that it will be able to exploit them as it has done in Syria.
The groundwork for the advance now was laid at the beginning of the year, with the capture of Fallujah and other parts of Anbar. It was viewed at the time as the group taking advantage of Sunni unrest in Iraq while Syria remained the focus of interest. Instead, the province became the base for further strikes in Iraq, with bombings in northern Babil and southern Baghdad.
By April, Isis had taken control of Karma and Abu Ghraib to the west of Baghdad, and then the towns of Mahmoudiyah, Iskandariyah and Yusufiyah to the south of the capital.
Now Isis has taken Tikrit, Bayji, Jalula and Saadiyah, and is poised to move into Khalis and Baquba, the place where Zarqawi was killed carrying the "Baghdad Belts" map. The group's spokesman, Abu Mohammed al-Adnani, may declare the aim is to sweep on to the Shia holy cities of Najaf and Karbala, but attempts to capture the capital remain a more realistic prospect.
It could be, of course, that the current offensive may wither if US President Barack Obama orders air strikes and the Iraqi government forces, Shia volunteers and the Kurdish peshmerga form a cohesive coalition.
But that, one assumes, won't mean the end to jihad and the plans to establish the Islamic State in Iraq and Syria.
- Independent