Complex sentence: In contrast to his predecessor, Dobri Bozhilov, Bagrianov was known for his largely pro-Western views and he saw as his mission removing Bulgaria from the war before the arrival of the Red Army and so attempted to open negotiations with the Western Allies.
Split into simpler sentences: In contrast to his predecessor, Dobri Bozhilov, Bagrianov was known for his largely pro-Western views. He saw his mission as removing Bulgaria from the war before the arrival of the Red Army and so attempted to open negotiations with the Western Allies.