Final answer:
Palestrina primarily composed paraphrase Masses, often based on fragments of plainsong, adhering to the Renaissance era's use of polyphony and smooth vocal textures.
Step-by-step explanation:
The type of Masses that Palestrina mostly composed, which account for about half of the 104 attributed to him, are known as paraphrase masses. These Masses were usually based on a fragment of plainsong or another pre-existing melody. This practice was part of the broader trend in Renaissance music where composers often employed a cantus firmus or paraphrased a melody, using it as a structural basis for the Mass. Palestrina's approach to composition was particularly notable for its smooth polyphonic texture, clarity in voicing, and use of the melodic interval of the third, which became more acceptable and treated as consonant during the Renaissance era.
It is important to note that aside from paraphrase Masses, the historical progression of sacred music also encompassed polyphony that developed from the monophonic Gregorian chants of the medieval period. By the era of the Ars nova, polyphonic music became increasingly complex, although this complexity was subsequently mitigated by a renewed focus on vocal part smoothness during the early fifteenth century.