What is the passage mainly about?

Because he wrote his name so that it could be read easily, John Hancock has a place in the dictionary.
    John Hancock was a wealthy man who helped the patriots in the American Revolution. He was president of the Continental Congress. He was also governor of Massachusetts and one of the first men to sign the Declaration of Independence. Yet he is remembered best for his large signature.
    The story is told that when Hancock sat down to sign the Declaration of Independence, he said that he would write his signature large enough for John Bull to read without his glasses. (John Bull stands for England, as Uncle Sam stands for the United States. )Hancock’s signature on the Declaration is four and three-quarters inches long- an inch longer than his usual signature. Today John Hancock can be used to mean any person’s signature.