Modern trim elements and moldings can be traced back to buildings designed by Greeks and Romans. It was these ancient architects who determined that for a building to be aesthetically pleasing it had to have certain elements such as plinths, columns and entablatures. You can see in the figure on the right that the entablature is comprised of the Cornice, the Frieze and the Architrave.
Cornice has an Italian derivation meaning “ledge”. It is comprised of horizontal decorative moldings which crown any vertical building element (walls, doors, windows, columns). The function of the cornice is form a projection from which dripping rain water will fall free of the buildings elements below. Thus projecting gable ends, roof eaves, and gutters provide both form and function.
Today, baseboards serve as modern plinths and door casings mimic miniature columns, while crown moldings have supplanted the entablatures of ancient times. Perhaps most amazing is that virtually all of the molding profiles available today are based on combinations of eight basic shapes established by classic Greek and Roman architecture.