Complex sentence: Welsh was appointed Professor of Ecclesiastical History in the University of Edinburgh and was Moderator of the General Assembly of the Church of Scotland on the occasion of the Disruption of 1843-and he headed the secession on the day of the exodus.
Split into simpler sentences: Welsh was appointed Professor of Ecclesiastical History in the University of Edinburgh. He was Moderator of the General Assembly of the Church of Scotland on the occasion of the Disruption of 1843, and headed the secession on the day of the exodus.