You are using an out of date browser. It may not display this or other websites correctly. You should upgrade or use an alternative browser.
alternatehistory.com
Joseph I of Portugal didn't have male heirs, and in order to secure the throne of Portugal to his dynasty he arranged the marriage of his eldest daughter (Mary I) to his brother (Peter III), which happened in 1760.
However, WI Peter had died before this marriage? There would be no Braganzas left to find a husband to Mary and continue the rule of the family.* So, given that it would be happening under the context of the Seven Years War, who could be a possible candidate to be king consort of Portugal and founder of the new dynasty?
*Well, there was Infante Manuel of Portugal, but would be over 60 at the time, and doesn't seem likely that the would have agreed to it anyway.