Music is the art of combining sounds that humans have been creating for thousands of years using instruments like flutes, harps, and lyres. By 1500 BC, cultures had developed many basic musical elements still used today like the guitar, scales, harmony, rhythm, and melody. Music theory seeks to understand how and why certain note patterns sound right or wrong to listeners. Key elements of written music include the staff, clefs, notes, alterations, time signatures, bars, tempo, and intervals between pitches.