"As I failed to answer every one of the sphinx’s riddles, I was unable to get past it to my gold."
-- letter from Mallory Twiddle (DP1)
Mr Twiddle was unable to access his High Security vault because of the difficult riddles asked by the Sphinx guarding it. He would personal prefer the return of dragons or security trolls to the front line at Gringott’s Wizarding Bank (DP1).
Although the date printed on the first Daily Prophet Newsletter (DP1) is 31 July 1998, the timeframe for this event is 1992-1993.
From the Web
Writing by J K Rowling on Pottermore: The Daily Prophet