It strikes me, reading medieval and ancient history, that all other ruling classes fought amongst themselves as much, if not more, than they combated the plebeian masses. The bourgeoisie, by contrast, engages in remarkably infrequent civil war, even if we include the World Wars, which were more national wars of conquest and defense, anyway. Notice that as soon as a large bourgeoisie develops in a post-colonial nation, civil conflict within the ruling class tends to sharply decline. From civil war, it degrades to mere threats of coups and civil discord, down to the acrimonious but petty political disputes which characterize multi-party regimes. Actually, this could be considered one of the great achievements of the bourgeoisie - bringing internal peace to most nations.