Long-time player of a lot of rpgs, but haven't touched the Birthright Setting in almost 20 years. Now my group has returned to it and I am DM'ing a new campaign, so I turned to this setting out of interest and looking for a little bit of help

Specifically, I am curious about a timeline of the most recent 100-200 years of Anuire, because I am finding some of the references in the Ruins of the Empire and Atlas of Cerilia source books kinda screwy.
Points in question:
- Diemed is said to have ruled Medoere and Roesone - but Roesone is said to have formed out of near-wilderness from bandits uniting under Daen Roesone 80 years ago?
- Medoere gained some kind of independence from Dimed "a century ago" from Diemed "weakened by the recent loss of Roesone" - but Roesone is only 80 years old??
- Daen Roesone formed Roesone 80 years ago, then ruled for 4 decades, while defending against Diemed. Then his son Morghar killed him and took over. And in the last 40 year, Roesone has been ruled by Morghar, his son and then now his granddaughter? Isn't that a bit weird to go through 3 generations in the same time space as Daen ruled all by himself?
If any of you have toyed around with the Diemed / Medoere / Roesone timeline or other campaign related matters, I'd like to hear about them as well

Thanks!