In the sixteenth century, especially in the areas around Venice and Padua, itinerant groups of professional actors began to perform comic plays based on masked caricatures of the social types found in northeastern Italy. The plays were improvised around scenarios that deployed the same set of masked comic types in varying relations to each other, usually serving to either facilitate or block a romantic plot involving a pair of unmasked young lovers. The masks were made of leather, formed over wooden molds, and covered only the upper part of the face, leaving the lower jaw and mouth free for dialogue. These plays were performed throughout Europe, having a profound influence on European theatre up until the present day. In the 20thh century there has been a revival of interest in these masks and in the Commedia dell'Arte traditition.