The Building of Barad-dûr

[Aiwendil]

I've recently noticed that there appear to be three somewhat contradictory statements in The Lord of the Rings and the 'Akallabeth' concerning when Barad-dur was first built.

In 'The Council of Elrond', Elrond, telling of the Last Alliance, says:

Originally Posted by Elrond

The Dark Tower was broken, but its foundations were not removed; for they were made with the power of the Ring, and while it remains they will endure.

In the 'Tale of Years' (appendix B), we read:

Originally Posted by Tale of Years

c. 1000 Sauron, alarmed by the growing power of the Númenoreans, chooses Mordor as a land to make into a stronghold. He begins the building of Barad-dûr.

Originally Posted by Tale of Years

c. 1600 Sauron forges the One Ring in Orodruin. He completes the Barad-dûr. Celebrimbor perceives the designs of Sauron.

And in the 'Akallabeth':

Originally Posted by Akallabeth

Already in the days of Tar-Minastir, the eleventh King of Niimenor, he had fortified the land of Mordor and had built there the Tower of Barad-dur

Now, these statements raise two questions. First, if (as ToY says) the One Ring was made around 1600, right at the end of the 600 year long building of Barad-dur, then how can Barad-dur's foundations have been made with the power of the Ring? The foundations, after all, surely must have been the first part of Barad-dur that was built (it's rather difficult to build a fortress from the top down!).

The second problem is that the reign of Tar-Minastir was, according to 'The Line of Elros', from 1731 to 1869. So, even if we assume that the Akallabeth is meant to place only the completion of Barad-dur, and not its whole construction, in the reign of Tar-Minastir, that still puts it more than a century later than is said in ToY.

It's perhaps worth noting that in earlier versions of the Tale of Years and of the Akallabeth the dates line up somewhat better: the earlier draft of ToY gives Barad-dur's construction as 900 - 1900 and the forging of the One Ring sometime between 1200 and 1500; and the earlier draft of the Akallabeth puts the building of Barad-dur during the reign of Tar-Atanamir, which at that time was 1790 - 2061. But still, there is the issue of Barad-dur's foundations being laid long before the Ring was made.

I don't know if there's all that much to say on this topic, but I do find it somewhat puzzling and was wondering what others make of it.