You can do that by just updating the wiki, no?
The wiki could work as a repository, or even a long region description. If people agree that whoever takes on lordship (or dukeship) of a region adds a bit of flavor to the region (preserving its history). Even a short line like "From x day to x day Lord Somethingorother controlled the land and heavily taxed the peasants." or "On x day the entire population was decimated" when starved/looted empty.
