The "Times of the Gentiles" started with the deposing of the last king of Judah, i.e. King Zedekiah, the last king to sit on Jehovah's earthly throne, which happened with the overthrow and destruction of Jerusalem and Solomon's temple in 607 BC, by the Babylonians, led by King Nebuchadnezzar, which heralded the beginning of the 70 (x 360 day) years of Babylonian captivity and which would not end until 538 BC, Dan,9:1,2. See also Ez, 21:25-27. From 607 BC and onwards, therefore, was to be the Gentiles time, which we know from Dan 4:16,23 was to last for seven periods of time.
In Dan, 4:10-37, we learn of another of Nebuchadnezzar's dreams, where he is depicted (as we later learn from Daniel's interpretation) as a giant, heaven high tree, he being the highest human (earthly) ruler of that time. The tree, as depicted by the king, we then learn is cut down, with only its stump left in the ground, but which is then banded with iron and bronze and then left in the grass of the field, to be drenched with the dew of heaven, amongst the beasts of the field until seven periods of time pass. Initially, we learn that this said time period is to relate to the king himself, during a fit of mindless incomprehension, imposed by Godly intervention, and that he himself is to languish in the field, as if a beast, eating grass, for 7 full years, at the end of which he is shown and comes to believe that it is Heaven that rules. We also learn, however, that the seven periods of time are to have further meaning, in that they are to last until ...."the Most High is ruler over the realm of mankind, and bestows it on whom He wishes, and sets over it the lowliest of men." Dan,4:17.
If, as I believe, the lowliest of men, is a cryptic reference to Jesus taking over the earthly kingdom, as opposed to heavenly kingdom (which He inherited after his ascension), at the end of Gentile rule, then the further meaning, as to the seven periods of time, has to span more than two millenniums. How long can we possibly, therefore, be truly talking about, when it comes to this duality of meaning.How long can we possibly, therefore, be truly talking about, when it comes to this "duality" of meaning??
In Luke 21:24, we see a definite reference to the Times of the Gentiles, but I see this as just a reminder that the said times still have a long way to go. The trampling of Jerusalem, by Gentile Nations started with Nebuchadnezzar, and was emphasized further under Vespasian and in particular his general Titus, in the 1st Jewish/Roman War of 66 AD thru 73 AD, which incidentally covered a 7 year time period, in its own totality, with 70 AD being, of course, a very significant center point. But that's another story.