Adrian Willaert is considered, if not as the inventor of the madrigal, at least as the composer by whom it was given its first artistic form. It may be regarded as the highest form of chamber-music of those days, written and composed for the refined and appreciative amateurs of the best social circles, principally in Venice and Rome. All composers of repute produced works in this favorite form; among others (beside the two most prominent, Willaert and Cyprian de Rore) Constanzo Porta, Constanzo Festa, Verdelot, Arcadelt, Orlandus Lassus, Orazio Vechi and Luca Marenzio, the last named being the best madrigalist of his time.
There were other favorite vocal forms of a more general character, which were composed according to a chosen metre, to which the poem was afterward set. The name given to this species of composition was _modus_ (still to be found in the Portuguese term for folk-song, _modinha_) or _aer_, and from this source was derived the modern name, air or aria, which signifies the manner of singing (as we say a person has a certain air or manner), and does not refer, as many suppose it does, to the medium of song; that is, the sound of vibrating air.
These forms of secular song were inspired, undoubtedly, by the beautiful poetry which enriched Italian literature at that period,--the age of Dante, Petrarch, Torquato Tasso and Bocaccio.
Petrucci published (1504-1508) as many as eight books of Frottole, some nine hundred numbers in all. These are characteristic, though primitive examples of Italian music, and mark the essential difference between that and Flemish music. The latter, like the Gothic architecture of the North, was developed organically from germs or motives, while the former corresponds to simpler forms, the grand curves and arches of Roman churches, within whose walls the pure and elevated harmonies of Palestrina have resounded through the centuries. The innovations which resulted from these new ideas rapidly became popular, and in the course of time, old church modes fell permanently into disuse.
The last noteworthy representatives of the polyphonic school of the sixteenth century were Orlando di Lasso (Munich), Giovanni della Croce (Venice) and, chiefly, Gregorio Allegri.