I read a good historical fiction/swashbuckler about Grainne (can't recall the title), but in it, she gives birth to a son on the ship during a sea battle. I wonder if this is truth or legend? I know it's a fact that she met with Queen Elizabeth to work out some kind of peace treaty.
She was quite q woman.
I think that part was true, or at least one reads about it in the non-fiction side of the library.
The story of Grace is so interesting that I'm surprised Hollywood hasn't picked up on it. It's got many of the elements they look for: fighting against the social norms & superpowers of the day, action, women in battle (think Jennifer Garner), early historical evidences of feminist outlook, musical accompaniment (there are songs sung in Irish bars even today about Grace O'Malley) possibilities for sequels/spinoffs & merchandising, even precedence -- Mulan was quite successful.