Now let it be recollected that this continual and astonishing decline of agriculture, and disappearance of the rural cultivators in the latter stages of the Roman empire, took place in an empire which contained, as Gibbon tells us, 120,000,000 of inhabitants, and 1600 great cities, was 3000 miles long and 2000 miles broad, contained 1,600,000 square miles, chiefly fertile and well cultivated land, which embraced the fairest and most fertile portions of the earth, and which had been governed for eighty yers under the successive sway of Nerva, Adrian, Trajan, and the two Antonines, with consummate wisdon and the most paternal spirit.[14] The scourge of foreign war, the devastation of foreign armies, were alike unknown; profound tranquillity pervaded every part of the empire; and a vast inland lake, spreading its ample waters through the heart of the dominion, afforded to all its provinces the most perfect facility of intercourse with the metropolis and the central parts of the empire.  Yet this period—­the period which Mr Hume has told us the philosophers would select as the happiest the human race had ever known—­was precisely that during which agriculture so rapidly declined in the Italian and Grecian fields, during which the sturdy race of free cultivators disappeared, and the plains of Italy were entirely absorbed by pasturage, and maintained only vast herds of cattle tended by slaves.

[14] “Quingena viginti octo millia quadringinta duo jugera, quae Campania provincia, juxta inspectorum relationem, in desertis et squalidis locis habero dignoscitur, iisdem provincialibus concessum.”—­Cod.  Theod. lxi. i. 2382.

What was it, then, which in an empire containing so immense a population, and such boundless resources, drawn forth and developed under so wise and beneficent a race of emperors, occasioned this constant and uninterrupted decay of agriculture, and at length the total destruction of the rural population in the heart of the empire?  How did it happen that Italian cultivation receded, as Tacitus and Gibbon tell us it did, from the time of Tiberius; and equally under the wisdom of the Antonines, as the tyranny of Nero, or the civil wars of Vitellius?  Some general and durable cause must have been in operation during all this period, which at firest depressed, and at length totally destroyed, the numerous body of free Italian cultivators who so long had constituted the strength of the legions, and had borne the Roman eagles, conquering and to conquer, to the very extremities of the habitable earth.  The cause is apparent.  It was the free importation of Egyptian and Lybian grain, consequent on the extension of the Roman dominion over their fertile fields, which effected the result.  Were England to extend its conquering arms over Poland and the Ukraine, and, as a necessary consequence, expose the British farmer to the unrestrained competition of Polish and Russian wheat, precisely the same result would ensue.