Revelation 16:
12 And the sixth angel poured out his vial upon the great river Euphrates; and the water thereof was dried up, that the way of the kings of the east might be prepared.

When members of the Early Church read the above verses of the Sixth Vial of the Book of Revelation, they immediately understood the message. They knew through the writings of the Prophets, what happened in History during the year 536 BC. At that time, the Children of Israel were in captivity in Babylon, the Euphrates River passed right in the midst of Babylon. Half of the City was built on the East Side of the Euphrates and the other half on the West Side. Merchants' ships came on the Euphrates to the quays of Babylon which also had secure gates to protect the City.

Jeremiah 50:
38 A drought is upon her waters; and they shall be dried up...

Jeremiah 51: ... and I will dry up her sea, and make her springs dry.

Euphrates, the Great River, is wide and deep, this rendered Babylon impregnable since it was also protected by high walls all around the City.

Jeremiah 51
39 In their heat I will make their feasts, and I will make them drunken, that they may rejoice, and sleep a perpetual sleep, and not wake, saith the Lord.

Jeremiah 51:
57 And I will make drunk her princes, and her wise men, her captains, and her rulers, and her mighty men: and they shall sleep a perpetual sleep, and not wake...

It is reported by the Prophet Daniel that Belshazzar the king of Babylon made a great feast to a thousand of his lords and drank wine in the vessels of the Temple of Jerusalem which was destroyed by his father Nebuchadnezzar.

Daniel 5:
4 They drank wine, and praised the gods of gold, and of silver, of brass, of iron, of wood, and of stone.

Cyrus with his army had been digging deep trenches and during the Festivity, he diverted the Euphrates. Cyrus and his Army marched through the dry bed of the Euphrates. Being drunk, the guards of Babylon left open the Gates of the Quays. The army of Cyrus, walked through the open gates, invaded Babylon and Conquered the City.

Isaiah 45:1
Thus saith the Lord to his anointed, to Cyrus, whose right hand I have holden, to subdue nations before him; and I will loose the loins of kings, to open before him the two leaved gates; and the gates shall not be shut;

In Revelation 11:8, Jerusalem is also called Sodom and Egypt, so when members of the Early Church read about the water of the Euphrates was dried up, they knew what this meant.

Revelation 14
2 And he cried mightily with a strong voice, saying, Babylon the great is fallen, is fallen...

Revelation 14
4 And I heard another voice from heaven, saying, Come out of her, my people, that ye be not partakers of her sins, and that ye receive not of her plagues.

The Early Church got the message loud and clear, they knew Jerusalem would be besieged and destroyed!

Make sure to read these Studies:

Revelation 16:12 Euphrates' Water was dried up, that the way of the kings of the east might be prepared
https://www.brighteon.com/80b41162-0921-4a5b-8f19-78c56b9da36d

Second Coming of Christ - exact Timing in Revelation
https://www.brighteon.com/6a326ade-3c97-4503-9bf4-7d687453b6df

Revelation 17:13 And I saw a woman sit upon a scarlet coloured beast
https://www.brighteon.com/6495c51d-7680-4f12-a263-6205150b08b2

You may not like to click on links, search the titles on Brighteon.

Relevant Studies on Brighteon:

The Seventh Trumpet and the End of the World
https://www.brighteon.com/d5b6016b-cebf-4dcf-90a9-36005814634b

Book of Revelation: secret chronology of the sixth Trumpet
https://www.brighteon.com/43c084e3-8675-42e8-96f0-82787d8ff1f0

The Seventh Trumpet and Secrets of the Book of Revelation:
https://www.brighteon.com/c5272a02-da6e-44f5-98d8-40cf3bc784bf