Complex sentence: Joanna Mercedes Alessandra Sturm (born July 9,1946), philanthropist, historian is a great-granddaughter of 26th U.S. President Theodore Roosevelt and the granddaughter of Alice Roosevelt Longworth.
Split into simpler sentences: Joanna Mercedes Alessandra Sturm (born July 9,1946) is an American philanthropist and historian. She is the great-granddaughter of Theodore Roosevelt, the 26th President of the United States and the granddaughter of Alice Roosevelt Longworth.