To Anna, I'm not sure I see how placing the story in Canterbury would insult the King. People were actually going there on pilgrimages. Those pilgrimages weren't insulting to the King, especially considering that while Thomas a Becket was killed by supporters of the King, it was almost 200 years before the Canterbury Tales were written. Setting it in another place, like Italy (Egypt would have been predominately Muslim at the time, like it is now, so Christians wouldn't really have been going there) would have made the story difficult to relate to and it would have lost the value of its social criticism, but I don't think it had anything to do with the King. Also, I doubt he would have been so busy "frolicking" that between that and, you know, ruling a kingdom he wouldn't have bothered to really look at what Chaucer was writing, considering he was paying for Chaucer to write.