Original: In the session of the League of Nations on December 15, 1928 in Lugano Stresemann formulated a furious charge against Poland because of these crimes which were well known to the League of Nations.
Simplified: In the session of the League of Nations on 15 December 1928 in Lugano Stresemann formulated a furious charge against Poland because of these crimes which were well known to the League of Nations.