Short answers, pulled from the story.
Poggio Bracciolini discovered the manuscript of Lucretius's De rerum natura in the year 1417 within a German monastery library. This text had been lost for centuries and contained Epicurean philosophy that scholars initially ignored.
Francesco Petrarca, known as Petrarch, is considered the Father of Humanism and was born in 1304. He was a poet and manuscript collector who believed studying pagan civilizations could strengthen Christianity.
The fall of Constantinople in 1453 caused Byzantine Greek scholars to migrate to Italy. These émigrés brought ancient Greek works that Latin scholars had never possessed and taught the language of Plato and Aristotle.
Renaissance humanists sought to reconcile their faith with pagan philosophies by using classics to illuminate the truths of the Gospel. Marsilio Ficino synthesized Platonism with Christianity while Erasmus defended Epicurean ideas as harmonious with Christian doctrine.
The adoption of large-scale printing after 1500 transformed the humanist movement from an elite pursuit into a cultural force. This technology allowed humanist ideas to reach a wider audience across France, Germany, and England.