This iconic drawing illustrates Leonardo’s own interpretation of Vitruvius’ written account of how the ideal proportions of man, with arms and legs outstretched, would fit into the geometric forms of the square and the circle. In order to achieve a coherent solution, Leonardo chose to adjust the relationship between the circle and the square - only the centre of the circle coincides with the navel, while the centre of the square is located somewhat lower.

In this drawing, he corrected inconsistencies in Vitruvius’ measurements of the human figure, guided by his own observations and deductions based on the study of life models. Through the precision of his own measurements, he created an image that is accepted as a true representation of Vitruvius’ findings, and a perfectly credible albeit constructed image of the ideal proportions of the human figure.