This brought to Rome a century of internal peace, which marked the beginning of the Renaissance. The ruling popes until the first half of the 16th century, from Nicholas V, founder of the Vatican Library, to Pius II, humanist and literate, from Sixtus IV, a warrior pope, to Alexander VI, immoral and nepotist, from Julius II, soldier and patron, to Leo X, who gave his name to this period ("the century of Leo X"), all devoted their energy to the greatness and the beauty of the Eternal City and to the patronage of the arts.