The development of sheet music was only made possible thanks to a harmonic relationship that has been defined as a miracle.

The octave, or the interval between the same note one pitch higher or lower, is the fundamental building block of music in the same way words are built from letters and numbers are built in collections of ten.

In music theory, this takes the form of scales comprising eight notes, but where did this come from, and was this always the way music was written?

The earliest notation dates back to 1400 BC and is tragically incomplete.

Known as the Hymn to Nikkal, the earliest song is actually written around a heptatonic scale designed for the nine-string lyre.

Because it is so specifically based around a single instrument, it is closer to a guitar tab than traditional notation. Whilst incomplete, it has been translated enough to be played.

The Ancient Greeks had a dedicated musical notation system as well, often inscribed above Greek letters to create both music and lyrics. This was seen with the Delphic Hymns and the Seikilos epitaph, the oldest complete musical composition.

This song, found carved on a tombstone in what is now modern-day Turkiye, was a musical 

elegy and thankfully captures an entire musical tradition lost following the fall of Ancient Rome.

The evolution of notation came exceedingly slowly, focused on capturing different elements of melody but often struggling to capture rhythm and tempo. The problem with this is that music notation, until the 17th century, was almost unplayable except to people who already knew the music.

Sheet music largely evolved alongside the musical instruments and technology to produce them, and it was not until the Mainz Psalter in 1457 that the printing press had developed the sophistication to mass-produce sheet music.

By the end of the 17th century, fixed note lengths, bars and most of the standard aspects of musical notation came about, which allowed for the Classical Era of music and a golden age of composition.