Complex sentence: Realizing it is a message from the illusionist, Uhl re-examines the events in his head and concludes that Sophie and Eisenheim staged her death so she--and Austria--could be free of Leopold.
Split into simpler sentences: Realizing it is a message from the illusionist, Uhl begins to re-examine in his thoughts all recent events. He concludes that Sophie and Eisenheim staged her death so she and Austria could be free of Leopold.