Complex sentence: Samuel David Benedict Chatto is the first son of Daniel Chatto and Lady Sarah Chatto "née" Armstrong-Jones and is a grandson of Princess Margaret, Countess of Snowdon and a great-grandson of Queen Elizabeth, the Queen Mother.
Split into simpler sentences: Samuel David Benedict Chatto is the first son of Daniel Chatto and Lady Sarah Chatto "née" Armstrong-Jones. He is a grandson of Princess Margaret, Countess of Snowdon and a great-grandson of Queen Elizabeth, the Queen Mother.