The Draenei used to live on a planet called Argus and were known as the Eradar. The Draenei were watched over by the prophets Velen, Archimonde and Kil`jaeden. The Draenor had lived on Argus for many years unaffected by the changes going on in the universe.
Some of Eradar became corrupted (among the Eradar that was corrupted were Archimonde and Kil`jaeden) by Sargeras forcing the others on the run. Prophet Velen assisted by the Naaru were transported across space in the craft `Tempest Keep` to the planet of Draenor. It is at this point that they changed their names from Eradar to the Draenei. The name Draenei means `Exiled` in their language. They lived in peace with the Orcs for years on Draenor. The Burning Legion caught up with the Draenei on Draenor and in ensuing battles, the planet Draenor was destroyed. All what is left of Draenor is an asteroid known as Outlands.
The Draenei were forced to flee once more and came to Azeroth, settling on Azuremyst Isle on Azeroth. The Draenei joined forces with the Alliance (Human, Gnome, Dwarf, Night Elf). At the time of them joining the Alliance, the Pandarens had not yet been discovered and the Worgens were still living in Gilneas closed off from the rest of Azeroth.
Copyright: Blizzard Entertainment