The Quwwatu’l Islām Masjid in Delhi is the first congregational mosque, built under a settled Islamic power in India by the end of the twelfth century. Although the local Indian builders, mainly Hindus and Jainas, found themselves in a position of extreme dependency on the newly established Islamic power, that destroyed their own sites of worship, the edifice they created expresses some intriguing cultural fusions. The presentation will show that although the local artisans created this mosque under strict instructions provided by the new Muslim rulers, they managed to actively influence and shape the development of this Friday Mosque as well as of early Islamic architecture in India more general, exhibiting some fascinating artistic freedoms. Through the employment of a number of different forms of re-use, the foundations for a distinct Indo-Islamic architectural style were laid, that includes many integrative elements.