In the second decade of the 15th cent. Italy—primarily Florence—took the lead in the formation of an art that was to affect Europe profoundly for more than 500 years (see Renaissance art and architecture). Political stability was established in several regions, and powerful ruling families produced the patrons of art that made the artistic flowering possible. Donatello, Brunelleschi, and Alberti were among the first to look consciously toward classical antiquity as a model for their work. They, with Masaccio, whose style recalls Giotto's monumentality, began to devise the optical system of perspective. They also set a high artistic standard that was emulated by succeeding generations.