The pentathlon became an Olympic event in 708 BC during the 18th Olympiad. It included 5 events: discus, javelin, long jump, running, and wrestling. During other Panhellenic Games, running and wrestling were held as separate events as well, but jumping, discus, and javelin were only held as part of the pentathlon.
According to mythology, the pentathlon was established by the hero Jason. He combined the five events, and awarded the prize to his friend Peleus (who came second in every event but was the winner in wrestling).
The exact order in which the five events were conducted is not known. It is most likely that the first event of pentathlon was jumping or running. It is certain, however, that wrestling was the final event.