Medieval chivalry and the law of nations: another source of international law, with ongoing lessons for our time.

…Chivalrous ideas did not die out without having borne some fruit. In so far as they formed a system of rules of honour and precepts of virtue, they exercised a certain influence on the evolution of the laws of war. The law of nations originated in antiquity and in canon law, but it was chivalry which caused it to flower. The aspiration after universal peace is linked with the idea of crusades and with that of the order of chivalry. Philippe de Mézières planned his ‘Order of the Passion’ to ensure the good of the world….

The share which the ideas of chivalry have had in the development of the law of nations is not limited to these dreams. The notion of a law of nations itself was preceded and led up to by the ideal of a beautiful life of honour and of loyalty….

The influence of chivalry on the development of the law of nations nowhere appears more clearly than [in L’Arbre des Batailles of Honoré Bonet, prior of Selonnet in Provence]. Though the author is an ecclesiastic, the idea which suggests his very remarkable conceptions to him is that of chivalry. He treats promiscuously questions of personal honour and the gravest questions of the law of nations. For example, ‘by what right can one wage war against the Saracens or other unbelievers’, or, ‘if a prince may refuse the passage through his country to another’. What is especially remarkable is the spirit of gentleness and of humanity in which Bonet solves these problems. May the king of France, waging war in England, take prisoner ‘the poor English, merchants. labourers of the soil and shepherds who tend their flocks in the fields’? The author answers in the negative; not only do Christian morals forbid it, but also ‘the honour of the age’. He even goes so far as to extend the privilege of safe conduct in the enemy’s country to the case of the father of an English student wishing to visit his sick son in Paris.

Johan Huizinga, The Waning of the Middle Ages