Just as iron rusts from disuse... even so does inaction spoil the intellect.

The eye is the window of the human body through which it feels its way and enjoys the beauty of the world.

He who loves practice without theory is like the sailor who boards ship without a rudder and compass and never knows where he may cast.

Study me, reader, if you delight in me, because on very few occasions shall I return to the world, and because the patience for this profession is found in very few, and only in those who wish to compose things anew. Come, oh men, to see the miracles that such studies will disclose to nature.

Now do you not see that the eye embraces the beauty of the whole world? It counsels and corrects all the arts of mankind... it is the prince of mathematics, and the sciences founded on it are absolutely certain. It has measured the distances and sizes of the stars it has discovered the elements and their location... it has given birth to architecture and to perspective and to the divine art of painting.

You must grow in patience when you meet with great wrongs, and they will then be powerless to vex your mind.

O painter skilled in anatomy, beware lest the undue prominence of the bones, sinews and muscles cause you to become a wooden painter from the desire to make your nude figures reveal all.