The Python of Delphi was a creature with the body of a snake which was dwelling on Mount Parnassus in central Greece. Wherever it went, it would diffuse obnoxious smell and spread mischief and death.
Python was once sent out by Zeus’ wife Hera to chase Leto, Zeus lover, when she became pregnant from him, so that she couldn’t settle anywhere to give birth.
By the time Apollo was only 4 days old, he decided to take revenge and went to the creature’s cave Python to seek after him. At the moment the creature faced Apollo, it started boiling with rage and lunged at Apollo to devour him. But Apollo was faster and managed to throw an arrow to Python, piercing him right on its forehead.
Python cried of terror and his screaming could be heard all over the canyons of Mount Parnassus. It struggled hard to survive but in the end it surrendered to death.
This filled Apollo with joy and he happily took his lyre and started playing a song of victory, giving joy to people all around. This was the moment Apollo became the god of the Music. Right after he finished his song, Apollo took the creature and buried it under the slopes of Mount Parnassusl; on its surface he built the oracle of Delphi, also known as the "Pythia".
However, Apollo had committed a crime and according to the laws of Mount Olympus he had to be purified. So Zeus ordered from Apollo to institute the Pythian Games at Delphi so that host athletical and musical competitions could be hosted. So Apollo did and took part himself in the games; from then on, the Pythian Games were being held every four years in Apollo’s honor .