Complex sentence: The Gosforth Cross were first identified in 1886 by the amateur antiquarian Charles Arundel Parker in his book entitled The Ancient Crosses at Gosford and Cumberland.who demonstrated that the cross showed scenes described in the "Poetic Edda".
Split into simpler sentences: The Gosforth Cross were first identified in 1886 by the amateur antiquarian Charles Arundel Parker in his book "The Ancient Crosses at Gosford and Cumberland". He demonstrated that the cross showed scenes described in the "Poetic Edda".