Various conflicting accounts are given in Classical Greek mythology of the birth of Artemis and her twin brother, Apollo. All accounts agree, however, that she was the daughter of Zeus and Leto and that she was the twin sister of Apollo.
An account by Callimachus has it that Hera forbade Leto to give birth on either terra firma (the mainland) or on an island. Hera was angry with Zeus, her husband, because he had impregnated Leto. But the island of Delos (or Ortygia in the Homeric Hymn to Artemis) disobeyed Hera, and Leto gave birth there.
It depends on the myth. Artemis' myths were largely relating to her worship and religion.
artemis did not because she was a myth.
No, Artemis did not have a shield in Greek myth.
Yes, it is a myth where Artemis killed the girl children (and Apollo the boys) of Niobe.
Artemis had no spouses in the original myth, although I heard a myth that said she was the spouse of Apollo.
It depends on which myth of Artemis you are referring to.
No. Artemis does not appear in the myth about Medusa.
Artemis was never 'defeated' in myth.
Artemis roamed among the wilderness and mountains in myth.
Yes, many.
She is a myth. You can not 'defeat' her.
the birth of the twins