Complex sentence: They were a long and notable line of Scottish seafarers who sailed the world's oceans as early as the 19th century; his father and grandfather were both sea captains as were four of his grandfather's brothers.
Split into simpler sentences: They were a long and notable line of Scottish seafarers who sailed the world's oceans as early as the 19th century. His father and grandfather were both sea captains as were four of his grandfather's brothers.