It was gabriel, which means something like strong one of god or god is my strength. gabriel identified himself explicitly to the husband of marys cousin, elizabeth (luke 1:19) when zacharias questioned the news that his wife would bear a son. We don't know if gabriel identified himself explicitly to mary, but luke reports that it was the same angel who visited her (luke 1:26). So, either gabriel did give mary his name and luke just didnt recount that part of the conversation or mary and elizabeth compared notes when they told their stories to each other and realized it was the same angel.
