Simplify the following text for a Grade 9 native English-speaking person.
Original: Following some initial setbacks , the war went exceptionally well for England ; the victories of CrÃ cy and Poitiers led up to the highly favourable Treaty of BrÃ tigny .
Simplified: The war went very well for England ; the victories of CrÃ cy and Poitiers led up to the Treaty of BrÃ tigny by which he gained a lot of territory .