The answers to your questions are,
1. They saw it as a threat and wanted to stop it.
2. Poitiers was fought ten years after the Battle of Crécy (the first major victory), and about half a century before the third, the Battle of Agincourt (1415). The effect of the defeat on France was catastrophic, leaving the country in the hands of the Dauphin Charles.
-Mabel <3
