"The science of pure mathematics, in its modern developments, may claim to be the most original creation of the human spirit. Another claimant for this position is music." - Alfred North Whitehead, *Mathematics as an Element in the History of Thought*

Ultimately, mathematics isn't about numbers, it's about patterns: understanding patterns, and understanding relationships between patterns. Music is also about patterns, or rather, music *is* pattern: patterns of sound in time. So it's not surprising that mathematics and music have had a close relationship, going all the way back to the ancient Greeks.