From the 1980s to the present, an artisan named Carlomagno Pedro Martínez has promoted items made this way with barro negro sculptures which have been exhibited in a number of countries.[6] Barro negro pottery can trace its origins to 2,500 years ago, with examples of it found at archeological sites, fashioned mostly into jars and other utilitarian items.[3][5] This innovation makes the pieces more breakable, but it has made the pottery far more popular with Mexican folk art collectors, including Nelson Rockefeller, who promoted it in the United States.[3][5] Doña Rosa died in 1980, but the tradition of making the pottery is carried on by her daughter and grandchildren who stage demonstrations for tourists in their local potters' workshop.In that same year, he created a mural in barro negro at the Baseball Academy in San Bartolo Coyotepec sponsored by the Alfredo Harp Helú Foundation.[6] This style of pottery is made in San Bartolo Coyotepec and a large number of small communities in the surrounding valley, where the clay that gives it its color is found.[4] In addition to a number of family workshops, including Doña Rosa's, the Mercado de Artesanias is an important attraction which brings visitors from many parts of Mexico and other countries.[13] Many different kinds of objects are made of barro negro including pots, whistles, flutes, bells, masks, lamps, animal figures with most being of a decorative nature and not for the storage of food and water.Valente Nieto, the sole surviving progeny of Doña Rosa, states that his family created the mezcal monkey.He claims that his father was a gifted sculptor, and mezcal owners came to their property requesting novelty bottles for the alcoholic beverage.