https://wccftech.com/total-war-saga-thrones-of-britannia/

Total War Saga: Thrones of Britannia will be the first installment in the previously announced Total War spin-off saga. These will be smaller titles focused on specific periods of time.

This one is set in 878 AD when the Viking invasion of Britain was over. The political outlook had the Norse warlords established while the kings of England, Ireland, Wales and Scotland had their own ambitions. There’s no set end-date, though the in-game content of Thrones of Britannia will cover up to 1066.