[William Cloud Hicklin]

"Young King" - the practice was much more general than just the Angevins - was a way of ensuring the succession. As the West Franks moved away from their Germanic traditions, particularly that of partitioned inheritance, getting the chosen heir crowned and anointed ahead of time - and receiving oaths of fealty - was a way to avoid what happened inter alia with Maud and Stephen, and before that with the Conqueror's sons (Robert Curthose did not give in happily). So it was a direct outgrowth of inheritance. There also was an echo of the Roman Tetrarchy, in that the Angevin empire was just too big (with salt water in the middle) for one King to respond to every crisis in anything like a timely manner. But what crises did the House of Finwe ever have to respond to in Aman?

(Also, Henry fils made a rotten Young King, considering he spent most of his reign rebelling against Dad. No English King ever did it again, the title Prince of Wales eventually serving)

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NB: Richard CdL was less a religious fanatic than he was a war fanatic. And there was nothing at all unusual about appointing a regent during the king's prolonged absence.