During the 1480s Leonardo began to study proportion and geometry, the theory of light and the principles of anatomy.  He believed increasingly in the scientific basis of painting – that a painting should strive to be an objective rendering of the observable universe – and he developed a plan to compile a treatise on the theory of painting.

As the human body was the principal subject matter of the Renaissance artist, Leonardo wished to find the link between an individual’s emotions, expression and pose, so that he could paint a figure more convincingly. Many of his early anatomical studies attempt therefore to understand the structure of the brain and nerves. But with the notable exception of a skull he had very little access to human material at this time, and was unable to get very far with this study. Leonardo’s anatomical studies lapsed for the next fifteen years.