There appears to be an inconsistency between the Twelve Tribes and the Twelve Duchies (and the current countries).

We know that Tuornen broke off from Alamie, that Roesone et al split from Diemed and that the actual Cariele family fled to Coeranys (which is why Coeranys claims to be a Duchy and Cariele is currently termed as a County).

My question, though, is what happened to Brosengae and where did Osoerde spring from? Why has Brosengae lost its place in the Twelve Duchies and why is Osoerde apparently in its place?

Code:
TRIBES      COUNTRY      DUCHIES
Anwe        Roele/Avan   Avanil
Boru        Boeruine     Boeruine
Mhora       Mhoried      Mhoried
Elaime      Alamie       Alamie
Deretha     Diemed       Diemed
Aeren       Aerenwe      Aerenwe
Bheallach   Bhalaene     (Ghoere)
Elin        Elinie       Elinie
Brosen      Brosengae    Osoerde ??
Gehaiste    Ghieste      (Ghoere)
Duireina    Taeghas      Taeghas
Carel       Cariele      Cariele