Brooks Adams 
The Law of Civilization and Decay [EPUB ebook] 

When the Romans first emerged from the mist of fable, they were already a race of land-owners who held their property in severalty, and, as the right of alienation was established, the formation of relatively large estates had begun. The ordinary family, however, held, perhaps, twelve acres, and, as the land was arable, and the staple grain, it supported a dense rural population. The husbandmen who tilled this land were of the martial type, and, probably for that reason, though supremely gifted as administrators and soldiers, were ill-fitted to endure the strain of the unrestricted economic competition of a centralized society. Consequently their conquests had hardly consolidated before decay set in, a decay whose causes may be traced back until they are lost in the dawn of history.