It was never a mere imitation of antique models, but rather an original effort to reinterpret Greco-Roman themes and principles. The revival of classical architecture was inaugurated by the architect, sculptor, and theorist Filippo Brunelleschi (1377-1446). His enthusiasm for an architecture of harmonious proportions was shared by his younger colleague, the multitalented Florentine humanist Leon Battista Alberti. In his "Ten Books on Architecture", Alberti argued that architectural design should proceed from the square and circle, the two most perfect geometric shapes.