BBC Online: Bloody Mary and the Burning of Cranmer: Fact sheet illustrates how Mary Tudor earned the nickname "Bloody Mary."
BBC: Mary I (1516 - 1558): The first queen to rule England in her own right, she was known as 'Bloody Mary' for her persecution of Protestants.
History of the Monarchy: Mary I: Concise profile from the official site of the Royal Family.
Kids' Zone: Queen Mary I: Profile of Queen Mary I for children.
Mary I: Biography of Mary Tudor, queen of England (1553–58).
Mary I: British Monarchs: Biography and portrait. From Britannia.com.
Queen "Bloody" Mary I Tudor of England: Short biography and list of resources related to the life of Mary Tudor.
Tudor Monarchs - Queen Mary I: Detailed biography examines Mary's childhood, her reign, her marriage, and her bitter rivalry with Elizabeth I. Includes portraits.