This is a tale that is nothing without a Cat.
Dick Whittington was a real person, and he was indeed Mayor of London.
There are many variations of the story, based on a play produced in 1606 with later additions and evolution over hundreds of years. 

A young man seeking fame and fortune in London befriends a Cat and makes an impression. He falls in love with his employers daughter Alice Fitzwarren, but soon is framed for robbery by the wicked King Rat. He is forced to sea upon the Saucy Sally with Captain C Barnacles to clear his name. After a brief visit to a far off island and helping the Sultan Of Swing, Dick defeats King Rat and returns to London to marry Alice and become the Mayor! ...Oh and he only had a little help from the Sprit Of The Bells.