Complex sentence: She presided over her house until her death, which occurred three weeks short of her 88th birthday, making Sarah one of the longest living First Ladies in American history, which Anna Harrison, Edith Bolling Wilson, Lady Bird Johnson and Bess Truman have lived longer.
Split into simpler sentences: She presided over her house until her death, which occurred three weeks short of her 88th birthday, making Sarah one of the longest living First Ladies in American history. Only Anna Harrison, Edith Bolling Wilson, Lady Bird Johnson and Bess Truman have lived longer.