Modern mosques in the West are all too often considered to be anachronistic pastiches of authentic historical examples that are literally out of place in the Muslim diaspora. Whereas this perspective has usually led to projections of nostalgia onto generalized communities, in this article I will take two prominent and enigmatic examples from the Netherlands and trace empirically how their designs have developed. Building on an expanding body of iconological studies of religious architecture, I will present an analysis of the different positions the Muslim patrons who initiated these buildings have taken up in Islamic politics. An empirical reconstruction of their prototypical selections, and how these were used to steer the architects towards the creation of desired drawings, makes their outcomes more intelligible. Whereas both mosques have been modeled on the same historical example, an underlying contestation of religious authorization has led to divergent forms of architectural authentication.