ground bass

ground bass, melodic phrase used repeatedly as a bass line. In its earlier form, developed in the 13th and 14th cent., the ground or basso ostinato [Ital.=obstinate] never varied in harmonization or pitch. The tenor, or pes, of Sumer Is Icumen In is such a ground. Another sort was developed during the 17th cent. by Purcell and his contemporaries. This ground was not rigid as to pitch, sometimes moving from bass to soprano. It was composed with varying melodies and harmonies in the upper parts. The result was often a series of variations as in the baroque chaconne and passacaglia. The device often has great dramatic effect. J. S. Bach and Handel made remarkable use of it.