It is my understanding that par came into being when bogey was starting to become irrelevant. The best players were able to play less than the bogey of a course on a regular basis. This led to the development of par, which in most cases was 6-10 shots lower than the bogey score.
Wayne, you could very well be right in that the reason for bogey being outdated was for handicapping purposes. Originally, handicapping was relative to players within a club rather than relative to the course. I think handicapping may have started to become relative to courses at the same time par was developing.
But this is all second hand info, so take it with a few grains of salt.
Ciao
Sean