The theory of proportions had a great fascination for Renaissance artists. Their works were not only intended to display artistic skill, they were meant to achieve harmony. Proportions in painting, sculpture, and architecture were like harmony in music and gave intense delight.
Proportion is not only found in numbers and measurements but also in sounds, weights time, and position, and whatever power there may be.
The Roman architect Vitruvius had transmitted some data of a Greek canon for proportions of the human figure and these were revived in the Renaissance. A drawing by Leonardo, known as the Vitruvian Man (Venice, Accademia), was reproduced in an edition of Vitruvius` book, published in 1511, in order to illustrate the statement that a well-made human body with arms outstretched and feet together can be inscribed in a square; while the same body spread - eagled occupies a circle described around the navel. The proportions of the human body are here related to the most perfect geometric figures and may be said to be integrated into the spherical cosmos.
Leonardo endeavoured to verify and elaborate Vitruvius` mathematical formulae in order to put them on a scientific basis by empirical observations, and for this purpose he collected data from living models.
Leonardo da Vinci: Notebooks
[Oxford World`s Classics]