Handbook of the Christian Knight

[2] During a stay in Tournehem, a castle near Saint-Omer in the north of modern-day France, Erasmus encountered an uncivilized, yet friendly soldier who was an acquaintance of Jacob Batt, Erasmus' close friend.

On the request of the soldier's pious wife, who felt slighted by her husband's behaviour, Battus asked Erasmus to write a text which would convince the soldier of the necessity of mending his ways, which Erasmus did.

The resulting work was eventually re-drafted by Erasmus and expanded into the Enchiridion militis Christiani.

Enchiridion makes reference to the Pauline "spiritual armor" metaphor of Ephesians 6,[4] which in the 16th century only gained in popularity as a result of Erasmus' work.

Scholars believe that in Albrecht Dürer's famous artwork Knight, Death, and Devil, the image of the knight (shown dressed in armor) can be interpreted from an Erasmian viewpoint to represent the knight who is able to vanquish his enemies by ignoring them "in his pursuit of Christian virtue".