staged genre in which singers are accompanied by instruments, arose at this time in Florence. Opera was developed as a deliberate attempt to resurrect the music of ancient Greece. Genres Principal liturgical (church-based) musical forms, which remained in use throughout the Renaissance period, were masses and motets, with some other developments towards the end of the era, especially as composers of sacred music began to adopt secular (non-religious) musical forms (such as the madrigal) for religious use. The 15th and 16th century masses had two kinds of sources that were used: monophonic (a single melody line) and polyphonic (multiple, independent melodic lines), with two main forms of elaboration, based on cantus firmus practice or, beginning some time around 1500, the new style of "pervasive imitation", in which composers would write music in which the different voices or parts would imitate the melodic and/or rhythmic motifs performed by other voices or parts. Several main types of masses were used: Cyclic mass (tenor mass) Paraphrase mass Imitation mass Masses were normally titled by the source from which they borrowed. Cantus firmus mass uses the same monophonic melody, usually drawn from chant and usually in the tenor and most often in longer note values than the other voices. Other sacred genres were the madrigale spirituale and the laude. During the period, secular (non-religious) music had an increasing distribution, with a wide variety of forms, but one must be cautious about assuming an explosion in variety: since printing made music more widely available, much more has survived from this era than from the preceding Medieval era, and probably a rich store of popular music of the late Middle Ages is lost. Secular music was music that was independent of churches. The main types were the German Lied, Italian frottola, the French chanson, the Italian madrigal, and the Spanish villancico. Other secular vocal genres included the caccia, rondeau, virelai, bergerette, ballade, musique mesurée, canzonetta, villanella, villotta, and the lute song. Mixed forms such as the motet-chanson and the secular motet also appeared. Purely instrumental music included consort music for recorders or viols and other instruments, and dances for various ensembles. Common instrumental genres were the toccata, prelude, ricercar, and canzona. Dances played by instrumental ensembles (or sometimes sung) included the basse danse (It. bassadanza), tourdion, saltarello, pavane, galliard, allemande, courante, bransle, canarie, piva, and lavolta. Music of many genres could be arranged for a solo