Complex sentence: Subsequently, the territory was annexed by Lithuania, and the "fait accompli" was eventually confirmed by the Council of Ambassadors in 1924 which was regarded as another humiliation for the Weimar Republic.
Split into simpler sentences: Subsequently, the territory was annexed by Lithuania, and the "fait accompli" was eventually confirmed by the Council of Ambassadors in 1924. This was regarded as another humiliation for the Weimar Republic.