The mosque they were calling for was never built, mainly due to red tape and administrative inertia. But, six years on, the Charlie Hebdo shootings by Islamist militants in Paris have catapulted the issue back to center stage.
"After Paris it's more urgent than ever to promote dialogue with Islam," said Milan's city manager for social policies Pierfrancesco Majorino.
"A mosque that can be controlled is better than lots of underground garages and circus tents."
At least 1.6 million Muslims live in Italy but there are only a handful of official mosques. That means most worship takes place in private houses or in the hundreds of makeshift Islamic cultural centers and Koranic schools dotted round the country.
Milan's center-left city administration has tried to speed up efforts to erect a mosque and has received some eight bids from builders. City officials hope to announce news in the next few months.
But while city hall is in favor, the anti-immigration Lega Nord party that runs the wider Lombardy region is set against.
"Either they recognize our values or they can go and build the mosque in their own back garden," Northern League leader Matteo Salvini said.
Concerns over housing and jobs have stoked resentment against immigrants among many Italians, as has the daily arrival of migrants on Italy's southern shores and the emergence of hardline Islamist militants across the Mediterranean in Libya, which some believe pose a threat to Italy's security.
Milan has a history of Islamist militancy. In the 1990s, radical preacher Anwar Shabaan led the Bosnian jihadist effort from Milan and set up what the United States said was “the main al Qaeda station house in Europe”.
In 2013 Abu Imad, a preacher at the city's best known Islamic center, in Viale Jenner, was expelled after time in jail on terrorist charges.
Lorenzo Vidino, an expert in political Islam, said that while some Italians favored giving more space for Muslims to practice their faith, they were concerned about the potential impact of radical preachers' views, for example on the role of women or homosexuality.
"It creates a mood music to which more radical groups dance," he said.
After Islamist shootings in France, Belgium and Denmark and with fears increasing about the possibility of militants coming to Italy from Libya and Tunisia, the government has taken steps to address concerns about Muslim radicalization.
Among measures introduced this year are a register for Muslim preachers and an Internet campaign to fight the threat of recruitment via the web.
In January, after the shootings in Paris, the Lombardy region passed new limits on building houses of worship, requiring any site to also have space for a car park twice the size of the building, making it difficult for any mosque to find such a location in near the center of Milan.
Until recently, Viale Jenner was so pinched for room, worshippers had to lay mats outside and pray on the street.
Many of those worshippers for Friday prayer now go to a one-time concert- and sports-hall, not far from the San Siro soccer stadium, that could soon become Milan’s first Grand Mosque.
"Our project includes a prayer area, as well as dedicated areas for social and cultural activities, a library, restaurant area and conference centers," said Davide Piccardo, coordinator of the Islamic centers federation Caim which has presented plans to build a mosque on the site, owned by the city.
Money is another problem. Rome's Grand Mosque was built, after some controversy, with Saudi Arabian cash. In the Milan tender, there is a measure requiring developers to clearly state the origin of any funding.
"The city council is stumping up the land but where are the Muslims going to get the money from to pay for the mosque?" said the Northern League's Salvini. "That's a total mystery."