Humanism spread new ideas about education, knowledge, and civic responsibility in 15th-16th century Italy. Ghiberti and Brunelleschi competed to design the Florence baptistery, with Ghiberti's graceful style recalling Greco-Roman works. Wealthy families like the Medicis commissioned many artworks and started libraries, allowing artists like Donatello, Leonardo, Michelangelo, and Raphael to develop styles influenced by classical forms and illustrate new techniques. Michelangelo's Sistine Chapel ceiling became one of the period's most famous artworks despite his difficulties with fresco painting.