I've got both layers of problems, though: the stuff I established in previous books, and the stuff history has established for me. If this were a secondary-world story, I could change around the dates of the Fenian bombings (which only happen in this novel, not the previous ones), but as it stands I can't.

Though admittedly, the thing that made me start swearing in this post was in the category of "things I did to myself." If I'd made a certain non-historical event happen at a different time of year, I could have shifted the events of this book, no problem.