The _Missa Papæ Marcelli_, which proved so important an instrument in the history of church music, is written for six voices, soprano, alto, two tenors, and two basses. Immediately upon its production its popularity became very great. Cardinals quoted poetry in its praise; the pope commanded that a special performance be given in the apostolic chapel, and that it be transcribed into the chapel collection in unusually large characters. Baini compares its grandeur to that of Thirty-third Canto of the Inferno. Curious legends as to its origin sprang up, and unauthorized 'arrangements’ went through several editions. A poor adaptation for four voices was made by Anerio, and others for eight and twelve voices by other followers of the Roman school. It is perhaps the best known example of the celebrated Palestrina style. In a classification of Palestrina’s work the German writer Hauptmann distinguishes three styles, corresponding generally to the master’s very early, adolescent, and mature years. The first shows markedly the influence of his Netherland predecessors and teachers. The melodies move along independently without 'melting into chords,’ and the predominating character is fugal and canonic. In this phase of his work he was still influenced by the 'evil fashion’ of the period, which for the most part subordinated the true meaning of the music to the display of contrapuntal science. This quality is shown occasionally, also, in later compositions, as, for example, in the mass with the well-worn _L’omme armé_ theme, wherein he boldly met the Flemish composers on their own ground and proved that he could write as learned counterpoint as they. In these examples he seems intentionally to have adopted the florid style of his predecessors, overlaying the theme with erudite contrapuntal figures, and rendering it elaborate and difficult.