Rondellus

A technique of three-voice composition cultivated in 13th-century England, or a piece composed in this manner. It uses the device known as voice-exchange. The exchange could be restricted to the two upper voices supported by a repetitive tenor (or pes), or it could be applied to all three. The only medieval writer to describe it was an Englishman, Walter Odington (c1300), although a Welsh account of 1198 clearly refers to the practice and early examples seem to come near the Welsh border. On the Continent it was known as an English practice from at least c1225; in continental treatises the term is generally found as the Latin for rondeau. Apart from the famous Summer Canon (which can be regarded as a potential multipart rondellus), no examples for more than three voices are known. The form died out, along with voice-exchange, after c1300.