This article analyzes the development and framing of Catalonia’s “Law on Centers of Worship”, an innovative law dedicated exclusively to the regulation of religious temples that was passed by the regional Parliament in 2009. The law was a legal novelty in Spain, as well as in Europe, where regulations pertaining to places of worship are typically folded into regional or municipal laws and ordinances dealing with zoning and construction. My analysis highlights how the law aimed not only to address the challenges generated by the proliferation of places of worship serving religious minorities, but also to legally reinforce and symbolically affirm Catalonia’s political autonomy and cultural distinctiveness vis-à-vis Spain. I place particular emphasis on how the temporal confluence of heightened nationalist mobilization, on the one hand, and tensions surrounding ethno-religious diversification, on the other, contributed to the development of a legal innovation that integrated the governance of religious diversity within the broader nation-building project. This article’s findings illustrate the role of historical timing and conjunctural causality in shaping the dynamic nexus between religion, law, and politics.