In the social sciences the public sphere, following the classic work of Habermas, is primarily considered as a space for rational deliberation, a safeguard of the spirit of true democracy, in permanent struggle with the forces of the market economy and capitalism. In contrast to this, and based on two books of historical sociology I published over the last years, which reassessed the links between the Renaissance and modernity, focusing in particular on the power of images, and on the social effects of the re-birth of theatre in Europe in the late Renaissance, I argue that the modern public sphere has fundamental theatrical qualities, and that it emerged jointly with the market economy. A central role in the process was played by the fairground, thus imprinting a carnivalesque urge to go beyond all limits, by turning the world upside down, on both the modern economy and the public sphere.