A 35 000 year old flute has been found in Germany, (for more information see Nature issue 460, page 663) which suggests that music was in quite an advanced form of development in early man. It's thought that language began in human populations between 50 000 and 100 000 years ago, meaning that music developed not long after that. It cements ideas that music developed naturally in early man for reasons of bonding, communication and spiritual ritual.
A further implication is that these early Europeans may have used the same musical intervals as are in use in the world today, suggesting that ideas of musical metre and harmony are universal. Fossil musical instruments are extremely rare since they decompose very easily and it is not known what other types of instruments were used, nevertheless this finding allows us to attach an earliest date to the invention of complex music. Before that, it is still assumed that percussion was the most ancient form of music, and probably developed concurrently with language as a means of communication over longer distances than speech.