Can you hear the difference in musical textures?

Listen to Hildegard of Bingen’s Alleluia, O virga mediatrix and Ma fin est mon commencement (My end is my beginning).The listening guides are on pp. 67 and 71 in the textbook, respectively.Although one of these is a piece of sacred music, the other secular, what do they have in common that points to their being written during the Middle Ages?Can you hear the difference in musical textures?Do you know of any other music that is monophonic or polyphonic texture?