Complex sentence: Initially it was relatively modest in size but over the years was enlarged, firstly in 1849 by John Fitzgerald and subsequently in 1875 and 1895 when the east and west wings were added.
Split into simpler sentences: Initially it was relatively modest in size but over the years was enlarged. Firstly in 1849 by John Fitzgerald and subsequently in 1875 and 1895 when the east and west wings were added.