William the Conqueror will be one of the spinoff’s leads, and he had a wife, Matilda/Maude of Flanders.
Of course, if Katheryn Winnick actually landed a role in the spinoff, it would be even more exciting!
If the new show stays true to history, she should be a significant factor, and would need a strong actress to fill those shoes.
One of the characters mentioned in the spinoff’s description is Freydis, and I could see her taking on that role, though she could easily fill any key character that wasn’t initially mentioned in the Vikings announcement.