 After he is thwarted by Cyrano long enough for her to be able to marry her sweetheart Christian de Neuvillette, he vengefully sends both Christian and Cyrano to do battle at the 1640 Siege of Arras, in which Christian is killed.At Arras, however, de Guiche shows gallantry toward Roxane and a willingness to sacrifice his life to protect her after she arrives at the battlements.In doing this, he wins Cyrano's respect, and later becomes one of his most loyal friends.