Fresco is the art of painting on plastered walls. This medium was one of ancient Greek civilization's art forms : interiors of villas and palaces were covered with fanciful impressions of life and nature in the Greek world. Fresco artists were widely patronized by royalty and the wealthier members of society.
A wall was prepared for painting with a thin layer of white lime plaster. Then, using an obsidian chip or other sharp instrument, the artist outlined the main features and sketched in important details. Next, the colours were applied, often while the surface was still moist so that they soaked in and made the painted images more durable.