During the Middle Ages music was seen as a gift from God and making music was a way of praising the heavens for that gift. If you look at paintings during this period, you'll notice that often, angels are depicted as playing different kinds of instruments. Some of the instruments used are the lute, shawm, trumpet and harp.
Sacred music was overcome by secular music by the 14th century. This type of music differed from sacred music because it dealt with themes that were not spiritual (non-religious). Composers during this period experimented on freer forms. One of the most important composers of that time was Guillaume de Mauchaut who wrote both sacred and secular music. Another important composer was Francesco Landini; a blind Italian composer. Landini wrote madrigals; a type of vocal music based on secular poems set to music that had simpler melodies.
John Dunstable was an important composer from England who used third and sixth intervals rather than the fourth and fifth intervals used earlier. Dunstable influenced many composers of his time including Gilles Binchois and Guillaume Dufay; two known Burgundian composers. Their works reflected early tonality. Tonality is a principle in music composition wherein at the end of the piece there is a feeling of completion by going back to the tonic. The tonic is the principal pitch of a composition.
Secular music flourished until the 15th century, afterward, choral music emerged.