The ruler was subject to the law and in which a representative body held him accountable to it.

From A Troublesome Inheritance by Nicholas Wade. Page 145.

The church used it power to back the idea of law, first of the Justinian code, a Byzantine codification of Roman Law that was rediscovered around 1070 AD, and then of canon law, the synthesis by Gratian of church laws through the centuries. Because law had the church's authority, sanctioned by a higher power, there emerged in Europe the novel idea that the ruler could not rule in defiance of the law and indeed owed his position to his role in upholding the law.

Feudal Europe was a collection of local barons installed in in largely impregnable castles. Kings tended to be the first among equals and had to negotiate with others to exercise power. They were obliged to take account of the concept that the law and not the king was sovereign. They could not tax or conscript peasants because those rights belonged to the feudal lords. Nor could they seize land because of property rights conferred by the feudal system.

National states emerged in Europe as part of a struggle between the king, the elites and other sources of power. The kings were seldom absolute rulers. The limitation on their powers was taken furthest in England, where Parliament raised its own armies, executed Charles I and forced James II to abdicate. The English state thus constructed a system, later followed by other European countries, in which the ruler was subject to the law and in which a representative body held him accountable to it.

OK. I am attracted to the idea that the concept of Rule of Law was a pivotal institutional/cultural development that explains a lot of divergence in world history between Europe and Asia.

But I can't help but feel that this is idea that is best viewed at a distance. Feels too much like a Just So Story. I am not sure that the argument above holds when examined closely. Seems like there are too many exceptions in Europe which leap to mind, and too many instances in India and China where at least moderately similar forces were in play at different times.

So maybe part of the story, but I don't think the complete story.