At the beginning of the episode Queen Catherine’s seer, Nostradamus, has a vision of war coming within the castle walls. His visions are not very clear and precise so that is all that he sees. Mary’s uncle, Claude DeGuise, visits French court. The English are on the border of Scotland so Mary needs soldiers from France to help and defend her country. King Henry refuses to send any. Tomas, prince from Portugal, visits France to make a deal with King Henry for wood. Mary asks Tomas for soldiers in exchange for wood from Scotland. Tomas asks Mary to become his wife and she considers breaking off the alliance with France. Francis sends Bash to send six companies to Scotland, but he comes back injured. Someone warned the English and they tried to stop Bash. Francis tells Mary that she should marry Tomas and she accepts Tomas’s offer of marriage. He sends his men to Scotland. Now as far as history goes Nostradamus is a fictional character who didn’t exist. Claude, Duke of Guise would have been Mary’s grandfather because he was her mother’s, Mary of Guise, father. He wasn’t her uncle. As far as Tomas goes he is also a made up character to add to the dramatic situations in reign.
Reign S1 E3