Complex sentence: She was the last British monarch of the House of Hanover; her son and successor Edward VII belonged to the House of Saxe-Coburg and Gotha, the line of his father.
Split into simpler sentences: She was the last British monarch of the House of Hanover. Her son and successor Albert, Edward VII, belonged to the House of Saxe-Coburg and Gotha, the line of his father.