How did musical notation preserve music before sound-recording technology existed?

Before the advent of sound-recording technology, musical notation served as a visual record and a set of instructions for performance, functioning primarily as an aid to memory or a means of communication. By providing a fixed reference, notation allowed compositions to reach levels of complexity that were difficult to sustain in a purely oral tradition.1

Early methods included:

• Neumes: Originating in the 9th–12th centuries, these graphic signs indicated the rise and fall of the voice. Initially, they served only as memory aids for singers who already knew the melody by heart.2
• Diastematic Notation: Between the 10th and 12th centuries, neumes were spaced on the page to create a continuous graph of pitch, eventually evolving into the staff system that fixed relative pitches.2
• Alphabetical Notations: Used since ancient times, these systems used letters to represent specific notes, forming the basis for modern note names (A–G).3

While these systems allowed music to be preserved and performed by others, they remained incomplete, often requiring performers to rely on traditional practices, ornamentation, and improvisation to fully realize the music's intended sound.4