Donna Troy's backstory has been an ever-evolving one, nearly from the time of her creation.
Originally conceived as Wonder Girl™, Donna was meant to be a teenage version of Wonder Woman™ as a founding member of the newly formed Teen Titans™. She became one of the team's mainstays, taking the independent name Donna Troy, and appearing only once in a Wonder Woman story during the Bronze Age.
Continuity was altered in the 1980s to recreate Donna as a girl chosen for training by the Titans of Myth, during which she adopted the name Troia™. In the 1990s, Donna was reestablished once more, but this time as a magical doppelganger of Wonder Woman brought to life, while Diana was out of action for a while.
Originally conceived as Wonder Girl™, Donna was meant to be a teenage version of Wonder Woman™ as a founding member of the newly formed Teen Titans™. She became one of the team's mainstays, taking the independent name Donna Troy, and appearing only once in a Wonder Woman story during the Bronze Age.
Continuity was altered in the 1980s to recreate Donna as a girl chosen for training by the Titans of Myth, during which she adopted the name Troia™. In the 1990s, Donna was reestablished once more, but this time as a magical doppelganger of Wonder Woman brought to life, while Diana was out of action for a while.