Comment by brudgers

I think the origin of life-changes-on-the-deathbed has its origin in the Christian practice of medieval kings, dukes, etc.

My understanding is that the ruling class would often remain unbaptized throughout their rule so they could do the things such people tend to do, and then partake of a deathbed baptism so they could still meet the requirements for going to heaven...

...power is having your cake and eating it too.