Complex sentence: Following Canadian Confederation, Tully joined the Ontario Department of Public Works in 1868, where he was involved in the supervising of the competition leading to the design of the Ontario parliament buildings at Queen's Park.
Split into simpler sentences: Following Canadian Confederation, Tully joined the Ontario Department of Public Works in 1868. He was involved in the supervising of the competition leading to the design of the Ontario parliament buildings at Queen's Park.