The Paradiso of Dante Alighieri

When Dante Alighieri chose Italian as the language for his Divine Comedy, he changed Western literature by bringing the poetry of the vates (divinely inspired seer poets) to the lay people. Most poetry before had been written in Latin for the clergy, and Dante's decision to write in Italian brought the language of the vulgar to the poetry of the divine. Along with his courtly love poetry, inspired by his profound obsession with his muse Beatrice, the three volumes of the Divine Comedy made Italian the literary language of Europe for several hundred years, and marked Dante as the most important author of his time.