This chapter considers that the massive development of the Roman urban planning of the period Giovanni Botero witnessed as he wrote his treatise has its own dynamic. It is part of a collective commitment aimed at rebuilding a multifaceted Roman greatness: first, the capital of the Roman Empire, then the capital of Christianity. Elaborating on Botero’s thoughts, the chapter discusses the epistemological added value of knowledge when produced in and by the city. The Roman urban space is where the first global empire took shape, but also the place where apostle Peter died and where the first Christian catacombs embedded the sacred dimension of the place into its soil. Using his idea of cities’ greatness, the chapter focuses on urban knowledge production and consider it, in Rome, as the result of a nonetheless unique ‘dispositif’. It traces the historical plasticity of the Egyptian-oriental reference provided by the obelisk in relation with Antiquity.