Prince Paul of Yugoslavia was the only son of Prince Arsen of Serbia, younger brother of King Peter I, and of Princess and Countess Aurora Pavlovna Demidova, a granddaughter on one side of the Finnish philanthropist Aurora Karamzin and her Russian husband Prince and Count Pavel Nikolaievich Demidov and on the other of the Russian Prince Peter Troubetzkoy and his wife Elisabeth Esperovna, by birth a Princess Belosselsky-Belozersky.