I'm currently taking an interest in honour codes and chivalry:

European Knights:

"The Knights Code of Chivalry and the vows of Knighthood
The Knights Code of Chivalry described in the Song of Roland and an excellent representation of the Knights Codes of Chivalry are as follows:

To fear God and maintain His Church

To serve the liege lord in valour and faith

To protect the weak and defenceless

To give succour to widows and orphans

To refrain from the wanton giving of offence

To live by honour and for glory

To despise pecuniary reward

To fight for the welfare of all

To obey those placed in authority

To guard the honour of fellow knights

To eschew unfairness, meanness and deceit

To keep faith

At all times to speak the truth

To persevere to the end in any enterprise begun

To respect the honour of women

Never to refuse a challenge from an equal

Never to turn the back upon a foe

Of the seventeen entries in the Knights Codes of Chivalry, according to the Song of Roland, at least 12 relate to acts of chivalry as opposed to combat."

Eastern Samauri:

Contempt for death, honouring superiors, politeness, the proper use of words and meanings, silence and self-reflective pose.

Eastern Assasin/Ninja:

To honour only and achieve a goal or mission once determined, trouble not about ends but means, vows of silence associated with mission or goal, eschewing conversation and social interaction.

Some of these ae culturally relative I think, arising in a particular context but is there anything perrenial about honour codes?

An interesting thing about the never refusing a challenge from an equal is that should a challenge be made and refused it may not imply cowardice or unwillingness to meet the challenge on the part of the other but that the other considers the challenge to be made by an inferior, either in standing or sills. I never knew that (I'm interested in duelling too).