Viderunt Omnes

A comparison between Perorin: ‘Viderunt omnes’ and “Agnus Dei”from La Messe de Nostre Dame the main similarity they being they both have a polyphonic texture. On the other hand, the piece Perotin: ‘Viderunt omnes’ is an organum which is in four voices, the singers of the different melodic parts sing either the original chant in long sustained notes, or sing rhythmically together on matched phrases. Also majority of the sung parts of the Mass being sung in simple monophonic texture. In the piece, ‘Agnus Dei” which has intertwining voices that creates a polyphonic texture. In addition, one could hear a harmonic effect made by the four voice parts. Aside from that the harmonies are not know to any ear sounding strange in comparison to modern chords.
The reason being composers at the time used melodies from the old church modes. Overall both pieces share a similar style know as “counterpoint” note against note, and point against point. Yes, you can hear chords in both of these unique pieces