Early medieval music came through the Church and Christianity. Liturgy within the religion was a traditional communal worship which included ceremonious music. This leads directly on to Gregorian chants, which were vocal-only sacred songs for Roman Catholics. These were originally sung by choirs, and whilst the simple repetitive monotone melodies can be sung alone, they are generally intended as congregational singing, whose structures can become much more complex and intertwined.
The influence if these psalms is evident both immediately after, in the Renaissance and Baroque periods, and by composers such as Bach and Mozart, and then more recently in entirely different genres. The feelings that Gregorian chants now evoke are both spiritual and unsettling, which are appealing effects for certain sounds. In new-age and world music, this was used seriously, peaking surprisingly with the album Chant by Benedictine Monks, and in extreme music such as heavy metal and techno it was incorporated to evoke an other-worldliness.
Movies have also used the stereotypical chants for their benefit, particularly in England, where it was affectionately mocked in Monty Python's Holy Grail, and eerily affecting in The Wicker Man.
Through the medieval period, there was also music played by instruments. The most common when relating to these sounds are woodwinds such as the flute, plucked such as the harp, and strings such the violin. Instrumental music was more likely to be played for secular, or non-religious, purposes. This could be as entertainment for theatre, at a congregation for dance, or at a court performance for aristocracy. The music was often rhythmic improvisations, but as singers were added to the instrumentals over the years, became increasingly structured into songs.
The influence of these also continues today, less so in popular music, but in genres that respect ancient traditions such as these. Both orchestral classical music and folk music at times use instruments, melodies and techniques from the sounds on the medieval period, and its powerful primitive effect is one that is likely to be harnessed for many years more.