Osama bin Laden and his number two man, Ayman al-Zawahiri, would have first met Abu Musab al-Zarqawi around 1999, just after he had been released from a Jordanian jail and made his way to Afghanistan.
Al-Zarqawi went there to set up a training camp in the western part of the country for a small group of his Jordanian followers known as Tawhid, an organization that aimed to overthrow the Jordanian government.
During this period, al-Zarqawi had no wish to attack the United States, as al Qaeda's leaders had already decided to do, and his relationship with al Qaeda was as much competitive as it was cooperative.
After the fall of the Taliban in Afghanistan in the winter of 2001, al-Zarqawi fled the country to Iran and made his way to northern Iraq sometime in 2002. He then started planning to attack American forces in what turned out to be the lead up to the U.S. invasion of Iraq in April 2003.
Al-Zarqawi's group of mostly "foreign fighters" was small in number, no more than 1,500 at any time, but had an important strategic impact on the Iraq war.
It has been the foreigners who have conducted by far the largest numbers of suicide operations -- up to 90 percent -- and it is those operations that helped spark the incipient Sunni-Shia violence in Iraq. This unrest forced the United Nations and many other international organizations to withdraw from the country.
For this reason, bin Laden was delighted when in the fall of 2004 al-Zarqawi announced publicly that he was renaming his group "Al Qaeda in the Land of the Two Rivers," i.e. Iraq. Al-Zarqawi also pledged bayat, a religiously binding oath of allegiance to bin Laden, who he described as his emir, or prince.
So far so good as far as bin Laden was concerned. But by 2005, al Qaeda's leaders were worried that al-Zarqawi's beheadings of civilians were turning off popular support for their jihad in Iraq. Al Qaeda's leaders were also deeply concerned about al-Zarqawi's efforts to provoke a Sunni-Shia civil war in Iraq.
While bin Laden and al-Zawahiri, both of whom are Sunni fundamentalists, may privately consider Shias to be heretics, they have never said this publicly. Al-Zarqawi by contrast has referred to the Shia as "scorpions" and has organized suicide operations against some of the holiest Shia sites.
The concerns of al Qaeda's leaders about al-Zarqawi's use of beheadings and his campaign against the Shias were underscored in a letter sent from al-Zawahiri to al-Zarqawi that U.S. military forces discovered in Iraq last year. In the letter, al Qaeda's number two gently suggested that it was time to end the beheadings and to start acting as more of a political leader in anticipation of the eventual U.S. withdrawal from Iraq.
In recent months, al-Zarqawi has stopped beheading his victims, but he has not let up in his campaign against the Shia. Upon hearing the news of al-Zarqawi's death, bin Laden and al-Zawahiri likely will release audiotapes indicating their joy that al-Zarqawi has finally received what he has always wanted -- martyrdom at the hand of the infidels.
But privately, they may hope that al-Zarqawi's successor in Iraq is more amenable to taking directions from al Qaeda central, which is located somewhere on the Afghan-Pakistan border. Viewed this way, al-Zarqawi's death could bring bin Laden some relief.