Complex sentence: He was a key figure in the talks that led to the end of the Bosnian war with the Dayton Accords, and the formation of the Federation during the Bosnian War, and has been described as a "moderate" politician.
Split into simpler sentences: He was a key figure in the talks that led to the end of the Bosnian war with the Dayton Accords, and the formation of the Federation during the Bosnian War. He has been described as a "moderate" politician.