The 18th and 19th centuries were a time of great upheaval. Revolutions in thought, in politics, in economies and production, and in warfare led to unprecedented and rapid cultural change. Enlightenment thinkers questioned everything, especially the nature of truth itself, concluding that the only truth is our own truth, and even that truth does not exist at all. A perfect society, then, would be one built only by the use of human reason, rather than the eternal truths of God which, they falsely concluded, did not exist at all. These new ideas led to revolution across Europe that rewrote the structure of society and geographic and political boundaries. The Church pressed on, however, in her mission to make disciples of all nations, and many saints rose to the occasion to defend the Truth of Christ.