R(icerca)re sopra Cantai mentre chʹi arsi (di) Cypriano
original Madrigal by Cypriano de Rore --- Il primo Libro de Madrigali Cromatici a Cinque Voci(Venetia, 1552)
I compared it to Cypriano's original madrigal, and it is treated quite liberally, omitting parts of the cantus part as appropriate. For example, in the following passages, the red framed parts are omitted.
bar1-33 : A part
bar33-73 : B part
http://aeolianconsort.chakin.com/Anonymous.htm
