Find the best castanets lessons, classes, and instructors on HeyKiki and learn how to play castanets. Historians are unsure of where the instrument was first used and by whom. What is known, though, is that it made appearances in ancient Rome, Greece, Moorish cultures and the first inklings of Spanish civilization. Basically, castanets are two hardwood shells strung together by rope and used for metronomic purposes, or keeping a beat throughout a song. In America, they are called "clankers," which is a good portrayal of the noise the instrument actually makes.