The first session of the symposium Tolerant Europe analyses in depth the ideas of some of the greatest philosophers of the eighteenth-century. Giuseppe Foscari examines the views expounded by John Locke in his Letter concerning toleration (1689). He does so by stressing the relationship between the notion of religious tolerance and the way European politics were conceived and constructed in the Age of Enlightenment. The second paper, by Matthew D’Auria, looks at Montesquieu’s dichotomy between a tolerant European and an intolerant Islam, highlighting the weight such an understanding had on the Montesquieu’s political visions of Europe. The paper by Silvana Sciarrotta focuses instead on the Voltaire’s Treaty on tolerance (1763) and on his ideas about the Quakers and their capacity, ‘as Europeans’ oppressed because of their religious beliefs, to create in the New World a tolerant society so difficult to build within Europe itself. The final paper of the session, by Maria Laura Lanzillo, highlights the ambiguity of Voltaire’s views about Europe which were compatible with universalistic political concepts – especially the notion of tolerance – as well as imperialist and expansionist ideas.