If you are looking any code of coduct for noble, use the real one that was create in the french era. Divide the noble in two class (Sword and Gown) Sword are military, blood heritage and the knight Noble (one everyone know, those who get call Blue Blood)
The Gown are rich and powerful merchant who bought their title to the King, but need to pay a due every year to keep it (way to have money)
Sword : can't work with their hand (this is ignoble to use your hand to work (no tailor, no carpenter, not blacksmith, nothing mostly other then learning the way of sword), most live with the money of their landship, if they act "ignoble" they lose their title as Noble and felt in disgrace
Gown : mostly can work (trade and merchant), but their title isn't a legacy so their childreen most pay the amount to the king to become a noble.
The Gown are rich and powerful merchant who bought their title to the King, but need to pay a due every year to keep it (way to have money)
Sword : can't work with their hand (this is ignoble to use your hand to work (no tailor, no carpenter, not blacksmith, nothing mostly other then learning the way of sword), most live with the money of their landship, if they act "ignoble" they lose their title as Noble and felt in disgrace
Gown : mostly can work (trade and merchant), but their title isn't a legacy so their childreen most pay the amount to the king to become a noble.
Tell me how your heart's in need as I drown you in the sea. Look me in the eye, I'm clear this is your time, face down beneath the waterline.Gazing into the deep from love to death in a time span of seconds. -Deliverance, Opeth-