One way was that Renaissance art used classical Greek culture as a subject such as Botticelli’s “The Birth of Venus” (about mythology) or Raphael’s “The School of Athens” (about ancient Greek philosophers). Previously in the Middle Ages, these subjects were unheard of in European art. Starting in the 14th Century, humanist patrons of art began to commission artists to create works about these classical themes instead of the usual Christian subjects that had been the standard in medieval art.
Another way humanism influenced Renaissance art was in how artists depicted the natural world. Naturalistic painting began to flourish with Giotto in the early 1300s; previously, in the Middle Ages, people were not depicted realistically because doing so was not a priority for medieval painters. They didn’t see any special beauty in the human form. Humanists in the Early Renaissance, however, argued that the human body was a beautiful creation of God, so it should be respected. Afterwards, painters and sculptors began to study anatomy closely in order to properly portray the beauty of the body. Thus, Leonardo, Michelangelo, Raphael, and others were able to depict figures so accurately. This also ties in with the ancient Greeks’ love of the ideal human form as it was presented in their sculpture.