During the Crusades, William of Tyre and Jacques of Vitry mention Lebanese Phoenicia in its Graeco-Roman borders and limits, undoubtedly based on the administrative and ecclesiastical geographies still known in the Roman Empire.

Under the Ottoman Empire, the former province of the Lebanese Phoenicia was present only in titles used by local Rûm Christians of the Patriarchate of Antioch and All the East.

[8] Due to mass administrative reforms and edicts directed at Phoenice Libanensis with the goal of preventing further pro-Sassanid raids and invasions, the province was now ruled by two ducēs during the reign of Justinian I.

[9][10] In the edict dating from c.535–539 of Justinian the Great on the province of Phoenice Libanensis, the emperor demanded that the governor restrain the ‘powerful households’, as he declared that the lawlessness of such regions' magnates made him "feel too embarrassed even to speak of the enormity of these people’s errant behaviour, and of how they have bodyguards protecting them and an intolerable number of people behind them, all committing barefaced banditry.

"[11] In October 527, Justinian’s reorganization of the military administration of Phoenicia Libanensis began, due to the pro-Sassanid Arab raids on the territory.

The emperor also ordered the newly appointed comes Orientis, Patricius, to reconstruct Palmyra, its churches, and its baths, and stationed a numerus and a number of limitane there.

Mundhir's raid as far as the Holy Land must have made the Roman authorities apprehensive about the safety of Palestine, and seeing that Mundir had taken a route from Palmyra to Emesa and Apamea.

Byzantium wanted to protect the interior of Oriens by intercepting Mundir at Palmyra to prevent him from penetrating deeper into Roman territory.

The edict's main concern was: the assertion of the power of the civil governor over the military and his elevation from praeses to moderator with the higher rank of spectabilis.

Procopius tells the story of the Strata dispute between al-Harith and Mundir, which served as Persia's pretext for the outbreak of the second Persian war with Byzantium.

[7] In February 452[b] the alleged head of John the Baptist was discovered in the monastery of Spelaion, in the diocese of Emesa, in Phoenice II.

[22] Following this event, Emesa—which had first been a suffragan of Damascus[23]—was "probably raised to the rank of honorary [ecclesiastical] metropolis of Lebanese Phoenicia in the second half of the fifth century" according to Julien Aliquot.