Complex sentence: The Eton Wall Game, which originates from Eton College, is a vigorous hybrid of rugby union and football played on a strip of ground 5 metres wide and 110 metres long next to a slightly curved brick wall (which was erected in 1717).
Split into simpler sentences: The Eton Wall Game, which originates from Eton College, has similarities to both the modern sports of rugby union and football. It is played on a strip of ground 5 metres wide and 110 metres long next to a slightly curved brick wall (which was erected in 1717).