During the seventeenth century there was a growing appropriation of the arts in support of the state: the state increasingly defined itself as a supra-individual, capable of strengthening identity and national ties. By focusing on several examples from the field of painting, we intend to show how in the Baroque period – unlike the Renaissance – this reason of state became one of the aims of art in the service of all governmental power: regardless of political orientations – absolutist and republican – the nation-state of the modern era used the arts to increase social cohesion in the military, religious and scientific fields. By analysing one of the scenes from Peter Paul Rubens’s Medici Cycle (1662–1625) and the Vow of Louis XIII by Philippe de Champaigne (1637), as well as landscapes, still lifes and Dutch scenes by Ambrosius Bosschaert the Elder, Jacob van Ruisdael, Gerrit Berckheyde and Jan Vermeer the deliberate contribution of Baroque painting to the consolidation of a sense of national unity is underlined. This mobilization of early nationalism in the modern period was largely carried out by imagination and fiction, as Benedict Anderson rightly pointed out, and painting proved to be an effective political instrument based on persuasion.