A further tidbit about the French annexation of Brittany was that Charles VIII and Anne de Bretagne never had any children who survived infancy, and when Charles VIII died in 1498, the crown, but not the duchy of Brittany, passed to Louis XII. Being already married to Charles' sister Jeanne de France, Louis had to have his marriage annulled before marrying Anne, thus keeping Brittany for France.
This was further complicated when Louis XII died, leaving only a daughter, Claude de France. Being female, she was barred from the throne but was able to inherit the duchy. The new king, François, married her in order to keep the inheritance.
Eventually, Brittany was declared united to the crown and this problem was avoided.