Complex sentence: By the 1840's the population had swelled to nearly 20,000, then disaster struck, the potato crop failed and famine stalked the land This most traumatic event in Irish history affected Ballydehob and the whole of West Cork in a most devastating Way.
Split into simpler sentences: By the 1840s the population had swelled to nearly 20,000, then disaster struck when the potato crop failed and famine resulted. This affected Ballydehob and the whole of West Cork in a most devastating way.