A round (also called a perpetual canon [canon perpetuus] or infinite canon) is a musical composition, a limited type of canon, in which a minimum of three voices sing exactly the same melody at the unison (and may continue repeating it indefinitely), but with each voice beginning at different times so that different parts of the melody coincide in the different voices, but nevertheless fit harmoniously together. It is one of the easiest forms of part singing, as only one line of melody need be learned by all parts, and is part of a popular musical tradition. They were particularly favoured in glee clubs, which combined amateur singing with regular drinking. The earliest known rounds date from 12th century Europe. One characteristic of rounds is that, "There is no fixed ending," in the sense that they may be repeated as many times as possible, although many do have "fixed" endings, often indicated by a fermata. "Row, Row, Row Your Boat" is a well-known children's round for four voices. Other well-known examples are "Frère Jacques", "Three Blind Mice", and, more recently, the outro of "God Only Knows" by The Beach Boys. A catch is a round in which a phrase that is not apparent in a single line of lyrics emerges when the lyrics are split between the different voices. "Perpetual canon" refers to the end of the melody leading back to the beginning, allowing easy and immediate repetition. Often, "the final cadence is the same as the first measure". History The term "round" first appears in English in the early 16th century, though the form was found much earlier. In medieval England, they were called rota or rondellus. Later, an alternative term was "roundel" (e.g., David Melvill's manuscript Ane Buik off Roundells, Aberdeen, 1612). Special types of rounds are the "catch" (a comic English form found from about 1580 to 1800), and a specialized use of the word "canon", in 17th- and 18th-century England designating rounds with religious texts. The oldest surviving round in English is "Sumer Is Icumen In" , which is for four voices, plus two bass voices singing a ground (that is, a never-changing repeating part), also in canon. However, the earliest known rounds are two works with Latin texts found in the eleventh fascicle of the Notre Dame manuscript Pluteo 29.1. They are Leto leta concio (a two-voice round) and O quanto consilio (a four-voice round).