But Saudi Arabia's recent moves on religion are seen by Belgian diplomat Dirk Achten, who headed a government delegation to Riyadh in November, as a 'window of opportunity'.'The Saudis are disposed to dialogue without taboos,' he told Belgium's parliament last month after the mission was hastily put together after the assembly urged the government to break Saudi Arabia's 99-year, rent-free lease of the mosque.But he also cautioned: 'Some do not, or barely, admit that this form of Salafism leads to jihadism.' Details of the mosque's handover are still being negotiated but will be announced this month, Belgian Interior Minister Jan Jambon told Reuters.But it is unclear who will operate the sprawling mosque complex, which receives about 5 million euros ( million) a year through the MWL which has for decades promoted a hardline interpretation of Islam at dozens of institutions worldwide The MWL has recently adopted a more conciliatory tone.In just over a year since being appointed, its secretary-general, Mohammad bin Abdul Karim al-Issa, has met with Pope Francis and taken a public stance against Holocaust denial.The diplomatic contacts, led by the countries' foreign ministers, were intended by Belgium to prevent what Jambon called an 'exaggerated response' from Saudi Arabia - indicating the Belgian government had sought to ensure there was no diplomatic backlash.This, he said, was 'under control' following a visit to Belgium last month by Saudi Foreign Minister Adel al-Jubeir.The centre's director, Jamal Momenah, made clear in 2015 that he did not want the Great Mosque to be seen as being connected to the radical Islamists of Molenbeek - the underprivileged suburbs where some of the Paris attackers lived.
In April 2012, the Saudi Arabian ambassador was alerted to the fact the Belgium government were unhappy with Khalid Alabri, who was then the Great Mosque's director.
Belgium has sent more foreign fighters to Syria per capita than any other European country.
Belgian officials now suggest the Muslim Executive of Belgium, a group seen as close to Moroccan officialdom, should run the Grand Mosque.
Bin Laden was a follower of Wahhabism, the original strain of Salafism which has often been criticised as the ideology of radical Islamists worldwide.
Yet many of Islamic State's positions are far more radical than Wahhabism, the ultra-conservative branch of Islam dominant in Saudi Arabia and founded by 18th century cleric Mohammed ibn Abd al-Wahhab.