III. THE STRING QUARTET.
It was not until the time of Haydn that the string quartet[31] came into being; a fact for which we may easily account by examining the instrumental parts of orchestral compositions before Haydn's time. We shall find the 'cello, for example, playing for the most part merely the bass notes that support the superstructure of the orchestra, and consequently entirely unaccustomed to individual parts of any difficulty. Another obstacle in the path of the string quartet was the slow development of the viola, which only gradually emerged from the older and more cumbersome types, such as the viola d'amour and viola da braccio. Haydn began by writing little quartets of the simplest possible kind—the first movement of the first quartet contains only twenty-four measures—but by constant practice throughout his long life he attained a complete mastery of the form. In his early quartets he usually wrote five movements, two of them minuets, but he soon settled on the regular four movement form which has remained ever since as the usually accepted model.