The Decline and Fall of the Roman Empire, Volumes 1 to 3 (of six): Introduction by Hugh Trevor-Roper: 1-2-3

The Decline and Fall of the Roman Empire: Volumes 1-3 of 6 (Everyman's Library)

The Decline and Fall of the Roman Empire (Volumes 4-6)

Livy: The Early History of Rome, Books I-V (Penguin Classics)