Supporters of the Taksim project argued there were not enough Muslim places of worship close to one of the city’s busiest hubs. Opponents saw it as a bid to impose a religious tone on the square, featuring a cultural centre dedicated to Ataturk which was demolished and is being rebuilt.
The mosque complex, with two towering minarets, will be able to host as many as 4,000 worshippers and includes an exhibition hall, a library, car park and soup kitchen, state-owned Anadolu news agency said. Pro-government newspapers hailed the new mosque.
Aksam's headline mocked critics who fear creeping religiosity: "It looks great. A mosque was built in Taksim and neither has sharia law come, nor has the republic collapsed," it said.
The inauguration also coincides with the date when protests began just 100 metres away in Gezi Park, before growing into massive protests against Erdogan's government which spread across Turkey in June 2013.
The Gezi protests began on 28 May, 2013 after demolition work began in one corner of the park the previous evening, knocking down a wall and some trees, drawing a small group of protesters who camped out at the site.
The anniversary of the protests is generally marked on 31 May, when the protests escalated. In June of that year, hundreds of thousands of people took to the streets in demonstrations against a plan to build a replica Ottoman barracks on Gezi Park.