The history of Western music truly begins in the darkened recesses of medieval monastic buildings, where voices joined together to form a collective embodiment of faith and wonder. Gregorian chant, attributed to the pope of that name but probably assembled over centuries, is the oldest music we can confidently hear as it was actually performed. These are melodies based on modes rather than the modern major and minor scales, which ride unfettered through afloat with no strict rhythm, allowing them to take on an almost timeless quality that was well matched to contemplation of the sacred. Singers breathed through large acoustic spaces, placing notes in resonance with one another — and effortlessly erasing the line between private voice and communal prayer. The purpose of this music was not entertainment, but spiritual elevation — with texts from scripture and in a language that transcended the vernacular.
With the passage of centuries, artists started to test new tunes with those old melodies. The first signs of organum (the earliest form of polyphony) occurred in the middle of the ninth century, when a parallel voice with which an interval of a fourth or fifth was also added above or below. This basic doubling added complexity to the texture and suggested that harmony was more than mere chance. By the 12th century, composers at Notre Dame cathedral in Paris went further. Léonin and Pérotin, whose names remain as early composers, elaborated polyphony in which multiple lines of melody intertwined at times against differing tempos. The upper parts moved with greater freedom, while the lower voice held long notes derived from the original cantus. Auditoriums had expanded to cavernous sizes and acoustics became more reverb-y, and composers wanted to use sound as a way of filling and remaking architectural space.
The transition from monophony to polyphony resulted in a radical transformation of musical thought. No longer satisfied with a sole melodic line, musicians began thinking about music in layers and dimensions. Rhythm got more organized, with patterns that could allow voices to align exactly as they went separate ways. The development of measured notation also allowed composers to indicate the regards in which a proportional relationship was intended, and liberated them from a dependence on pure oral tradition. Its chief interest continued to be imaginative creativity that functioned within sacred music. The voices in a motet may sing disparate texts at the same time, commingling Latin liturgy with French love poetry in ways that would have shocked and delighted medieval listeners.
The move to increased complexity mirrored a more general cultural turn in Europe. Trade routes were re-established, cities flourished and universities sprang up, where bright minds could meet and question. Music joined in that awakening as it grew more sophisticated and self-conscious. More promising was the emergence of composer signatures, evidence perhaps of a new sense of individual creativity even within religious ritual. The Gothic cathedrals springing up in France and beyond added both inspiration and practical necessity for a music that could project across vast spaces yet also reward careful attention to detail. Sound became architecture made audible.
The principles of the Western musical system were established at the very latest during the medieval period. Yet modes offered elastic structures for melody and rhythm became more precise with its notation; harmony, meanwhile, became a source of expression as it was shaped by controlled dissonance and resolution. Music’s ability to reflect and form human consciousness is evident in the leap from an interceding plainchant, sung amid monastic silence, to elaborating polyphony that soars beneath vaulted ceilings. It set principles that would develop through Renaissance and Baroque, beyond: A reminder that even the most complex of traditions starts with simple, heartfelt expression.