The document discusses theories about constellations from ancient Greece to modern times. It describes how the earliest constellations were identified by Homer around 6000 years ago and most were associated with myths by the 5th century BC. The modern boundaries of 88 official constellations were established by the IAU in 1922 and 1928. Modern constellations like Columba the dove and Monoceros the unicorn are more difficult to identify than classical ones because they contain fewer bright stars and are located in less prominent areas of the sky. Learning the classical constellations helps in finding the modern ones.