-Foreword- I have tried to adhere to the canons of both the Harry Potter and Mary Poppins universes as closely as possible.  In spite of rigorous research, the writing of this story necessitated guesswork and the invention of characters.  I have pieced together inferred some dates and characters.  I have incorporated both film and book canons for Harry Potter, but with emphasis on book canon.  In this story I have used the book universe for Mary Poppins, as it takes place in the 1930s, and allowed for easier dating.