People were already worshipping Artemis in Greece during the Late Bronze Age. Probably Artemis came to Greece with the Indo-European invaders in the end of the Early Bronze Age about 2000 BC, but the way people thought about Artemis also had a lot in common with a West Asian goddess, the Mistress of Beasts. Probably the Greeks mixed their ideas about Artemis with some West Asian ideas they also heard about.
Artemis as the Mistress of Beasts
(from the black-figure Fran�ois vase, about 570 BC)
To find out more about Artemis, check out these books on Amazon or at your local library:
D'aulaire's Book of Greek Myths, by Edgar and Ingri D'Aulaire.
Greek Religion, by Walter Burkert (reprinted 1987). By a leading expert, for adults. He has sections on each of the Greek gods, and discusses their deeper meanings, and their function in Greek society.