Complex sentence: In 1973, Gwyn joined "The Toronto Star" and worked as a National Affairs Columnist until 1985 and then became an International Affairs Columnist later that year which lasted till 1992.
Split into simpler sentences: In 1973, Gwyn joined "The Toronto Star" and worked as a National Affairs Columnist until 1985. He then became an International Affairs Columnist later that year; this lasted till 1992.