The ancients had only an intuitive grasp of how to represent three-dimensional reality on a two-dimensional surface. In about 1420, the Florentine architect Filippo Brunelleschi (1377-1446) demonstrated how he could accurately represent urban scenes using guidelines that converged to vanishing points on the horizon. Leon Battista Alberti (1404-1472) wrote down his ideas, and discussed their geometric principles in his 1436 book Della Pittura (On Painting). Brunelleschi’s techniques were quickly adopted by Italian painters and the concept of linear perspective developed in the Renaissance governed Western painting until the early years of the 20th Century when Modernism began to consider the world through multiple simultaneous points of view.