How did humanist ideals change the world of art in terms of the artists themselves and their artwork?

Humanist ideals came to the forefront in Europe during the Renaissance, roughly the fifteenth and sixteenth centuries. This period saw a burst of renewed interest in the classical literature of Greek and Roman authors. Humanism, which grew out of an interest in the classics, is, as the name indicates, a form of thought that places emphasis on the importance of humankind and human reason. Humanism shifted thinking away from the prior emphasis on God and faith, though these elements remained important.
Humanism brought themes from classical literature into art. Instead of art wholly concerned with Christian subjects, artists began painting stories from Greek and Roman literature. For example, Botticelli painted the birth of Venus, a Greco-Roman goddess. This was a significant shift in artistic sensibility.
Further, artists moved from being anonymous artisans imitating and reproducing conventional images. Instead, they became creative artists as we understand them today, producing unique works. As a result, artists themselves, like Botticelli and Michelangelo, began to be celebrated as stars and to sign their work.