 The fall of Constantinople led to the migration of Greek scholars and texts to Italy, fueling the rediscovery of Greco-Roman Humanism.Humanist rulers such as Federico da Montefeltro and Pope Pius II worked to establish ideal cities where "man is the measure of all things", and therefore founded Urbino and Pienza respectively.Pico della Mirandola wrote the "Oration on the Dignity of Man", considered the manifesto of Renaissance Humanism, in which he stressed the importance of free will in human beings.