I want to know the answer to the following question:
When was Longchamp isolated in the Tower of London?
All the background I'm provided with is that "Armed conflict broke out between John and Longchamp, and by October 1191 Longchamp was isolated in the Tower of London with John in control of the city of London, thanks to promises John had made to the citizens in return for recognition as Richard's heir presumptive.". Is that enough to answer the question?