Introduction - The concept of religion - The indult of Nicolò V and the old issues of conflict - The new issues of conflict - Other minor disputes - Gallican customs - The first concordat 1727, genesis and most significant legal aspects - Roman bargaining and the relationship with the congregations - The negotiations: from the first attempt at accommodation to the concordat of 1727 - The right of placitation, the exequatur and the placet: definitions - The reaction of the Church - Historical evolution of the institutes - From Clement XII to Benedict XIV a turbulent phase - Further upheavals