Who was the greatest ruler of all time?

[Rath]

Teo said:
You ask who was the greatest ruler of all time which suggest who had the most positive polices for the common good of society and the world at large.

But that list is full of military conquerors and long time rulers, might as well add Fidel Castro as well.

Fidel Castro hardly counts as a great conqueror. He only ever conquered Cuba.