Complex sentence: Following Edward IV's sudden death, possibly from pneumonia, in April 1483, Elizabeth Woodville became Queen Dowager for 63 days as her young son, Edward V became king, with his uncle, Richard, Duke of Gloucester, acting as Lord Protector.
Split into simpler sentences: Following Edward IV's sudden death, possibly from pneumonia, in April 1483, Elizabeth Woodville became queen dowager. Her young son, Edward V became king, with his uncle, Richard, Duke of Gloucester, acting as Lord Protector.