Complex sentence: He was the son of Major-General George Forbes, Viscount Forbes, and his wife, the Viscountess Forbes (née Frances Mary Territt); he succeeded his grandfather as Earl of Granard in 1837.
Split into simpler sentences: He was the son of Major-General George Forbes, Viscount Forbes and his wife Frances Mary Territt. Granard succeeded his grandfather as Earl of Granard in 1837.