 In 1921 as a delegate of the Chief-of-staff of the Polish Army, he took part in the League of Nations commission charged with defining the new Polish-Lithuanian frontier.Following the birth of his daughter, Tyszkiewicz left for Paris to resume his academic studies interrupted seven years earlier at Oxford.In 1921 he was admitted to the École des Sciences Politiques for a politics degree and simultaneously attended lectures at the Ecole centrale des arts et manufactures on automotive technology.