Complex sentence: She was born after nine years of childless marriage between William Cavendish, 5th Duke of Devonshire and his wife Lady Georgiana Spencer, the political hostess and socialite.
Split into simpler sentences: She was born after nine years of childless marriage between William Cavendish, 5th Duke of Devonshire and his wife Lady Georgiana Spencer, the political hostess. Her mother was Lady Georgiana Spencer, the famous political hostess and socialite.