The domination of Rome over the Mediterranean is the period of the greatest development of the olive tree. It is the period during which production, trade and consumption of olive oil interwove significantly with the structural development of agriculture and real estate, with the formulation of food policy, with the relationship between the economic importance of provincial management and the central politico-administrative apparatus of State.
During this period a few important improvements in oil technology were introduced, and numerous Latin writings in agronomy were written starting in the 2nd century BC. Authors such as Cato, Columella, the Sarsenas and others suggested to landowners the best techniques for olive tree cultivation and the best methods for pruning, fertilizing, harvesting and processing. 

At the end of the third Punic war, the whole Mediterranean area was involved in a process of expanding olive tree cultivation. During the Imperial period, Italic cultivation, which had been handed down by the Greeks to the local populations and the Etruscans, was replaced by that practiced in the Imperial provinces. In Betica (Andalusia) along the Guadalquivir river, the land was covered with huge olive groves, whose oil supplied the capital and the army stationed along the northern borders of the Empire, where olive trees could not grow.
Double oil lamp - 1st century AD 

In northern Africa olive groves covered extensive areas, often property of the Emperor, with hundreds of thousands of trees and numerous oil mills where countless numbers of slaves were employed.
The oil trade, together with the grain trade, were the most important of the Empire: every year entire fleets crossed the Mediterranean under the direct or indirect control of Rome, and entered the rivers.

In Rome a great pile of Betic amphorae, the Dressels 2O, was accumulated between the 1st and the 3rd centuries AD near the port on the Tiber. It attained a height of almost 5O meters (164 feet) and an area of about 22,000 square meters (238,000 square feet) and was called Mount Testaccio.
Under the reign of Constantine (4th century AD) there where 250 bakeries and 2,300 oil distributors in the capital of the Empire. They supplied citizens with oil for cooking, for cosmetics, for massage and body care at the baths, for the gymnasium, for lamps, etc.

The spread of the olive tree during the Roman period 

"As for us, the most just of men, who do not allow the transalpine nations to plant olive trees and vines in order to give greater value to our own olive groves and vineyards; acting in that way it is said that we act cleverly, which shows the difference between truth and wisdom." 

Cicero, De Repubblica, III, 9, 16