In the Assyrian period, Sibittibaal of Byblos became tributary to Tiglath-Pileser III in 738 BC, and in 701 BC, when Sennacherib conquered all Phoenicia, the king of Byblos was Urumilki.
 Byblos was also subject to Assyrian kings Esarhaddon (r. 681–669 BC) and Ashurbanipal (r. 668–627 BC), under its own kings Milkiasaph and Yehawmelek.

In the Achaemenid Empire (538–332 BC), Byblos was the fourth of four Phoenician vassal kingdoms established by the Persians; the first three being Sidon, Tyre, and Arwad.

Hellenistic rule came with the arrival of Alexander the Great in the area in 332 BC.
Coinage was in use, and there is abundant evidence of continued trade with other Mediterranean countries.

During the Greco-Roman period, the temple of Resheph was elaborately rebuilt, and the city, though smaller than its neighbours such as Tyre and Sidon, was a center for the cult of Adonis.
In the 3rd century, a small but impressive theater was constructed.
 With the rise of Christianity, a bishopric was established in Byblos, and the town grew rapidly.
 Although a Sasanian colony is known to have been established in the region following the early Muslim conquests of 636, there is little archaeological evidence for it.
Trade with Europe effectively dried up, and it was not until the coming of the First Crusade in 1098 that prosperity returned to Byblos, known then as Gibelet or Giblet.
In the Assyrian period, Sibittibaal of Byblos became tributary to Tiglath-Pileser III in 738 BC, and in 701 BC, when Sennacherib conquered all Phoenicia, the king of Byblos was Urumilki.  Byblos was also subject to Assyrian kings Esarhaddon (r. 681–669 BC) and Ashurbanipal (r. 668–627 BC), under its own kings Milkiasaph and Yehawmelek.
In the Achaemenid Empire (538–332 BC), Byblos was the fourth of four Phoenician vassal kingdoms established by the Persians; the first three being Sidon, Tyre, and Arwad.
Hellenistic rule came with the arrival of Alexander the Great in the area in 332 BC. Coinage was in use, and there is abundant evidence of continued trade with other Mediterranean countries.
During the Greco-Roman period, the temple of Resheph was elaborately rebuilt, and the city, though smaller than its neighbours such as Tyre and Sidon, was a center for the cult of Adonis. In the 3rd century, a small but impressive theater was constructed.  With the rise of Christianity, a bishopric was established in Byblos, and the town grew rapidly.  Although a Sasanian colony is known to have been established in the region following the early Muslim conquests of 636, there is little archaeological evidence for it. Trade with Europe effectively dried up, and it was not until the coming of the First Crusade in 1098 that prosperity returned to Byblos, known then as Gibelet or Giblet.
Byblos