The Med basin is unified for extended period after the fall of Rome. Any one polity controlling the overwhelming majority of the coast will count (we'll set the standard at Byzantine control at its Justinian height), with some flexibility if the remainder is under the control of a friendly state. Byzantine, Umayyad, Abbasid, Carolingian, Ottoman, whomever you think has the best odds.
What influence will this have on the economy, culture, politics, etc. of Europe, the Near East, and all the rest in the region?
What influence will this have on the economy, culture, politics, etc. of Europe, the Near East, and all the rest in the region?