[James the Just]

Like you, I've been working on a 'real life' chronology for Middle-earth and would like to share some thoughts and ideas on this fascinating subject. Most of what follows can be checked using the free Stellarium software (danger:addictive).

As for any theories that try to date events in the Third Age to a time before or in-between ice ages, they must be dismissed due to a lack of workability with the calendars described in the Appendix. Tolkien seemed to assume that the length of the year changed very little over time:

The year no doubt was of the same length now,1 for long ago as those times are now reckoned in years and lives of men, they were not very remote according to the memory of the Earth.

1 365 days, 5 hours, 48 minutes, 46 seconds.

The Return of the King, Appendix D.

Unfortunately this is not correct. If you went as far back as the Eemian interglacial around 130,000 years ago the length of the year, in terms of mean solar days, was about 365 days, 6 hours, and 5 minutes. This would result in a more than a 10 week difference in the days on the calendar for when seasons began between the start of the Second Age until the end of the Third. For instance, if the winter solstice was on Second Yule in the first year of the S.A. it would occur around mid-March by the time Bilbo and Frodo.
However around 10,000 years ago the year was only about 365 days, 5 hours, and 50 minutes. Using a more traditional chronolgy allows for less than a week's difference. So, for example, we could say that the solstice was originally on December 25 but gradually moved up to the Yules.

Another thing to keep in mind is the precession of the equinoxes. This will alter the visibility of many stars and constellations as it goes through its cycles. This puts even stricter limits on how deep into the past we can be. In Fellowship of the Ring there is a description of what I would presume to be Betelgeuse in Orion:

Away high in the East swung Remmirath, the Netted Stars, and slowly above the mists red Borgil rose, glowing like a jewel of fire. Then by some shift of airs all the mist was drawn away like a veil, and there leaned up, as he climbed over the rim of the world, the Swordsman of the Sky, Menelvagor with his shining belt.

The Fellowship of the Ring, Book I, Ch. 3, p. 120.

If we wish for Betelgeuse to even be seen above the horizon from the latitude of London then 9000 BC is as far back as we can go. 7000 BC to see the belt and about 5200 BC for Rigel. This pretty much kills some of the alternative chronologies in presented in NoME.

I think Tolkien got it right the first time.

“I imagine the gap [since the fall of Barad-dûr, TA3019] to be about 6000 years: that is we are now at the end of the Fifth Age, if the Ages were of about the same length as 2nd Age and 3rd Age. But they have, I think, quickened; and I imagine we are actually at the end of the 6th Age, or in the 7th”

(The Letters of J.R.R. Tolkien, letter #211, 14th October 1958, Michaelmas term)

This is usually interpreted to mean that the end of the Third age occurred around 4,000 B.C. But another way to read it is that it happened as long ago from the present as the length of the Second and Third Ages combined (about 6000 years). More precisely, if we consider the end of the Third Age to be on the fall of Barad-dûr, 6,459¼ years. Subtracting that from 1958 would date that epoch making event at 4502 B.C. But only if you took it very literally instead of for the approximation that it obviously is. So 4241 BC ought to be close enough.

But, alas, astromony yet again intervenes. Not many specific years will work. First of all the moon phases need to be in alignment with the seasons. If there is a full moon on the night of January 8 then the winter solstice should be around a week earlier.

The Moon, now at the full, rose over the mountains, and cast a pale light in which the shadows of stones were black.

The Fellowship of the Ring, Book I

I, Ch. 3, p. 374.

Even Venus must be taken into account.

The evening star had risen and was shining with white fire above the western woods.

She lifted up her white arms, and spread out her hands towards the East in a gesture of rejection and denial. Eärendil, the Evening Star, most beloved of the Elves, shone clear above. So bright was it that the figure of the Elven-lady cast a dim shadow on the ground.

The Fellowship of the Ring, Book II, Ch. 7, p. 472.

This doesn't leave us with a lot of options for choosing dates for the events in the stories. On the bright side, however, we can be more sure that we may have gotten it right if we did. Only about one in a hundred years can fit the bill astronomically.

Let's check some dates. 4241 BC? Nope. The full moon comes too soon and Venus is a morning star. The closest we can get is 4307±8 BC. The ± means that 4299 or 4315 BC may also work because both the Moon and Venus have similar 8 year cycles.

How about the aforementioned 4502 BC? Why yes! The winter solstice falls on 2 Yule, a full moon on January 8, and Venus is very high and bright in the evening sky on February 15. This is just plain dumb luck. We can take Tolkien's words literally and still have everything just right.

This still leaves us with determining the start of the other ages. Nothing seems to me more climatic in modern times than World War II. If it can be taken as a given that the Sixth Age began in 1 AD and that it ended in 1945 then its duration was 1944 years. Interestingly this is exactly 13½ yén. Since the Elvish calendar goes through a 3 yén cycle we could say that it's exactly 4½ cycles. If we wish to smoothly increase the length of the Ages as we go back in time we'd need a Fifth Age of 5 cycles and a Fourth of about 5½. This would give us a start date for the Fifth of 2160 BC.