In all that I posted already, the WTS acknowledges:
1. That Assyria ended as the second world power in the 17th year of Nabopolassar's kingship when Harran fell in 609.
2. That Babylon became the third world power until 539 when it fell, and Medo-Persia became the fourth world power.
Nabopolassar's 17th year 609 until 539 with the death of Belshazzar is when Babylon was the 3rd world power for 70 years, its greatest domination period. Although 7 different kings ruled during those 70 years, it was considered as 'one king' while it was the 3rd world power.
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[Insight- Particularly was this domination manifest during the seventh and sixth centuries B.C.E. when Nabopolassar, a native of Chaldea, and his successors, Nebuchadnezzar II, Evil-merodach (Awil-Marduk), Neriglissar, Labashi-Marduk, Nabonidus, and Belshazzar, ruled the Third World Power, Babylon. That dynasty came to its end when “Belshazzar the Chaldean king was killed.”]
Nabopolasar (626-605) = 21 years >>>17th year 609 Harran fell beginning the domination period for Babylon as the 3rd world power.
Nebuchadnezzar (605-562) = 43 years
Awil-Marduk (562 -560) = 2 years
Neriglissar (560- 556) = 4 years
Labashi-Marduk (556-556) 9 months
Nabonidus/Belshazzar (556 - 539) =17 years
[Isaiah’s Prophecy - True to the prophecy, for the duration of “one king”—the Babylonian Empire— He says: “These nations will have to serve the king of Babylon seventy years.” (Jeremiah 25:8-17, 22, 27) Evidently, the 70 years represents the period of Babylonia’s greatest domination— Different nations come under that domination at different times. But at the end of 70 years, that domination will crumble.]
[w53 7/15 -The rulers of Egypt were cruel, wicked men and greatly oppressed the people. Their government, which became the first world power, was a complete and miserable failure. It was conquered by Assyria, the second world power, likewise under the influence of Satan.]
[Insight - The Babylonian Chronicle B.M. (British Museum) 21901 recounts the fall of Nineveh, the capital of Assyria...This chronicle states, under the 17th year of Nabopolassar (609 B.C.E.): “In the month Duuzu, Ashuruballit, king of Assyria, and a large army of Egypt who had come to his aid crossed the river Euphrates and marched on to conquer Harran.” Their campaign against Haran did not succeed. The Assyrian Empire had ended.]
[w65 6/1 - Babylon succeeded Assyria as the Third World Power.]
[Insight - By now the Medes and Persians under command of Cyrus the Great were on the march to take over control of Babylonia and become the fourth world power. During the night of October 5, 539 B.C.E. (Gregorian calendar), Babylon was seized, and Belshazzar was slain.]