1. Medieval music became more elaborate as composers added complex melodies to simple chants. Wondering musicians like troubadours and minstrels entertained across Europe with various instruments, songs, and performances. 2. Guido d'Arezzo developed the musical staff and sol-fa syllables in the 11th century, advancing musical notation. Polyphonic compositions with multiple voices became popular in Paris works in the 12th century. 3. Guillaume Dufay was a renowned 15th century French composer known for his masses, motets, and development of a smooth Renaissance harmonic style.