Leonardo da Vinci, Study of horses, c.1490, drawing, Milan. Dimensions: 25 x 18.7 cm. Held in The Royal Collection, Windsor-Castle, Windsor, UK. The use of sketches and preparatory drawings increased dramatically in the late 16th century due to the increasing abundance of paper. Drawings such as these by da Vinci demonstrate the interest of High Renaissance artists in understanding the mechanics of bodies the better to represent these realistically.