Though the twelfth and thirteenth centuries do not, in England, show well-defined groups of musicians working toward a common end, such as constitute a 'school’ in the accepted sense, there can be no doubt that the English were ahead of their time in the early days of polyphony and that English music strongly influenced composers on the continent. Indeed a very considerable case for the actual origin of polyphony in England has been made out by recent historians of great authority, and the case is supported by the famous old English canon, 'Sumer is i-cumen in’--one of the earliest extant examples of polyphonic music. The date of this interesting composition is given by Rockstro[92] as not later than 1250. It is a charming melody, composed to a gay, naïve poem, in the form of a round, or canon, for six voices, and is supposed to have been written by John Fornsete, a monk of Reading. In some measures the parallel fifths and octaves show the influence of diaphony, while in others there is excellent counterpoint which might have been written at least a hundred and fifty years later. The imitation is not confined to short phrases, but is consistently carried through in the four upper voices to the close, over two independent basses. The harmony is rather limited, the F major chord being in great preponderance: but, on the whole, the canon shows a high degree of skill in polyphonic writing. It is, in short, a remarkable example of the working out of an inspired folk song with two systems of part writing, which, so far as we know, were not contemporaneous. One explanation of this apparent anomaly is that the composition, originally the work of a song writer of great natural genius, was later edited or corrected by a learned musician. Parallel octaves and fifths were not considered offensive in the thirteenth century, and such a learned scholar might easily have let them pass, while lifting other parts of the music to an artistic form considerably in advance of popular taste. It has been supposed, on the other hand, that the composition is really the single accidentally preserved specimen of a whole musical literature, which has otherwise been lost. In support of this latter theory it is urged that the art of imitation, as illustrated in the canon, must have reached a point of excellence beyond anything existing in France or Belgium at the time, and could only have been the product of a well-defined school. However the case may be, the song remains, an isolated but for its time brilliant example testifying to the freshness, vitality, and beauty of early English music.