Complex sentence: In January 1995 he made acting lieutenant-general and appointed Commander Bosnia and Herzogoena Command to command UNPROFOR in Sarajevo, and was responsible for breaking the siege of the city by creating the UN Rapid Reaction Force, and ultimately thereby bringing the war to an end.
Split into simpler sentences: In January 1995 he was granted the acting rank of lieutenant-general and appointed Commander Bosnia and Herzogoena Command to command UNPROFOR in Sarajevo. He was responsible for breaking the siege of the city by creating the UN Rapid Reaction Force, and ultimately thereby bringing the war to an end.