"whom they loved as much as their lord and foster-brother"
'The New Equipment' (1858)
Public Domain'The New Equipment' (1858) - Credit: Franz Eduard Meyerheim

This is the first of several references to the concept of fostering and to foster-brothers in The Mabinogion. Sending both male and female children to live with foster-parents was believed to have been common practice in early medieval Ireland. It was seen as a way of teaching the children further skills, and of reinforcing the bonds between families. The position regarding fostering in the Welsh situation seems to be less clear.

However, there does appear to be evidence of a tradition in medieval Wales whereby boys of noble birth were expected to master a range of skills known as the pedair camp ar hugain ('the twenty four accomplishments'), and these may well have been acquired whilst a boy was living as a foster-son. The 24 skills included various feats of strength, wrestling, swimming, archery, swordsmanship, falconry, heraldry, and declaiming poetry to the accompaniment of the harp.