These three areas obviously overlap quite frequently in chivalry, and are often indistinguishable. They have started to write in the language of those who defeated them.
It was also considered good manners to wash your hands before having a meal. The idea of chivalry — the knight in shining armor defending God, king, and country with sword and flawless character — is not a new one.
The particulars of the code varied, but codes would emphasise the virtues of courage, honour, and service. This process of confessionalization ultimately gave rise to a new military ethos based in nationalism rather than "defending the faith against the infidel". Thou shalt make war against the infidel without cessation and without mercy.
Thou shalt never lie, and shalt remain faithful to thy pledged word. The military orders of the crusades which developed in this period came to be seen as the earliest flowering of chivalry,  although it remains unclear to what extent the notable knights of this period—such as SaladinGodfrey of BouillonWilliam Marshal or Bertrand du Guesclin —actually did set new standards of knightly behaviour, or to what extent they merely behaved according to existing models of conduct which came in retrospect to be interpreted along the lines of the "chivalry" ideal of the Late Middle Ages.
Duties to God: this would contain being faithful to God, protecting the innocent, being faithful to the church, being the champion of good against evil, being generous and obeying God above the feudal lord.
His narrative and most of his topical discussions though, while well-researched and excellently presented, are not groundbreaking in terms of historical conclusions.