Jadwiga, as the Poles called her, was officially the King of Poland, rather than the Queen, since she was the ruler in her own right and not merely the wife of the King. Her great-grandfather was King Wladislaw the Elbow-High, the great unifier of Poland, who is included here only because his epithet is fun; her claim to the throne was never in question.
She had intended to marry William, Duke of Austria, but broke off the engagement at age thirteen to marry Jagiello of Lithuania. I tend to think that she was not the one to break it off, unless she was extraordinarily wise and not a little cynical at age thirteen. Nonetheless, her non-Christian husband converted for her, becoming King Landislaus II, and the union of their two kingdoms lasted more than four centuries.
Although things were pretty good between Jagiello and Hedwig -- well, good enough that she sold her jewels to raise enough money for the Krakow Academy to get it renamed Jagiellonian University -- at least one story suggests a little domestic friction.
Hedwig used to smuggle food from their home to give to the poor. These nocturnal missions were presented to King Jagiello as evidence that his wife was passing secrets to enemies. He busted her outside the palace one night with an apron full of food. Now it would seem to me that the food would be evidence of no greater crime than pilfering, and since she was also the King of Poland, she should have had much to fear. Times and genders being what they were, however, she was in mortal peril. But when she unfolded her apron, a bunch of roses fell out. Feather-headed women will take all kinds of risks for pretty posies, right? Get back inside, you silly girl.
A couple other miracles associated with her charity and piety were reported. The cross before which she used to pray is still hanging in Wawel Cathedral, and her sarcophagus rests beneath it. Look her up if you're ever in the neighborhood.