sentences:  Duke Peter, Alexandra's father, was the only surviving son of Grand Duchess Catherine Pavlovna, the fourth daughter of Tsar Paul I of Russia.Peter of Oldenburg followed a military career in the Imperial Russian Army and was also a scholar, a music composer and philanthropist.Alexandra’s mother, Princess Therese of Nassau-Weilburg, was interested in painting and like her husband was deeply involved in charity work, so much so that she was considered an eccentric.