What are the church modes?

The church modes, also known as the medieval modes, are a system of seven musical scales used in Western music, particularly during the medieval and Renaissance periods. These modes are derived from the diatonic scale and include Dorian, Phrygian, Lydian, Mixolydian, Aeolian, Ionian, and Locrian. Each mode has a unique pattern of whole and half steps, giving it a distinct sound and mood. The church modes were foundational for the development of Western tonal music and were often associated with specific liturgical functions in church music.