I want the Dagor Bragollach to happen in FA 455. Any compression of the story moves the opening of Season 5 later, rather than moving the Battle earlier. This is to avoid confusion later. There is no need for FA 310 to be the fixed date when Finrod meets Bëor; that's the 'flexible' point, whereas the date of the battle is fixed. So, working backwards.....
We need Beren to be grown and in his young 20's at the time of the Dagor Bragollach. He cannot still be a child in 455. So keep his birth in 432.
Barahir must be grown by the time Beren is born, so his birthdate would be FA 400-410.
Andreth, as Barahir's much older sister, would be born in FA 380-395 (She should be 15-20 years older than Barahir). This makes her 60-75 years old at the time of the battle. Since we wanted her to be old, but not so ancient that she can't escape with the refugees, this will work for her character, who will now noticeably outlive Aegnor. We do probably want to lean towards the earlier end of that range though, so say no later than FA 390 for her birth.
Bregor is Andreth's older brother. So, he would be born in the FA 375-388 range. That would make him 67-80 at the time of the battle. Presumably, he will not be fighting then, and it is his sons we will see taking his place (either Bregolas if we include him, or else Baragund and Belegund if we do not). Or we could do the 'old man gears up for battle' story with him, so that he leads his house into battle despite not being physically fit himself.
Boromir, as the father of Bregor, Andreth, and Barahir, would have to be alive at least 20 years before Bregor is born. So, FA 355 would make him 20-33 years old when Bregor is born, and 45-55 years old when Barahir is born. He will die sometime before the Dagor Bragollach.
So far, we're only about 20 years off from the published genealogy, having condensed one generation, essentially.
Now, Bëor originally dies as a man in his 90s in 355, 100 years before the Dagor Bragollach. If Boromir is going to be born in 355, then we likely want to shift Bëor's death forward about 20-30 years, so that Boromir is old enough to react to it, and we can get to Andreth being a character quicker. That's the real incentive to compress the timeline - if Bëor is the great-grandfather of the characters we want to get the audience to care about, then there is no 'overlap' time of them on screen - you have to tell the stories sequentially, waiting for Bëor to die before Boromir can be introduced. Bëor and Andreth cannot be contemporaries in the original genealogy, as he dies before she is born.
Placing the death of Bëor in FA 385 potentially allows Andreth to be a child at his funeral. Bëor is now born in FA 292. Naturally, this would mean that he doesn't meet Finrod in FA 310, but likely sometime in the 330-340 range.
Naturally, there is at least one more generation in there at this point, with either Baran or Boron existing to be Bëor's son and Boromir's father. To eliminate that generation, we would have to move up Bëor's timeline further, placing his death in FA 400, his birth in FA 307, and his meeting with Finrod in the FA 350's range.
One compromise would be to have a generation between Bëor and Boromir, but to have had that person (Bëor's son) killed in their wanderings before they reach Beleriand. Thus, Bëor has been raising his grandsons Boromir and Bereg, who are still very small children when Bëor meets Finrod, despite Bëor himself being in his late 40's/early 50s.
This timeline compresses about 50 years out of the story. We don't need to compress it down to the 80 years missing from Rhiannon's timelines, I don't think, but a little bit of compression is probably helpful for allowing our characters to overlap rather than live at completely separate times. I know I still have to work on the other two Houses, and some more adjustments will likely be needed to get all of them to work.
I realize there are some unusual quirks on this family tree, but I don't think anything on it doesn't appear in my own family tree over the past 4 generations, so it's nothing that unusual. I have a grandfather who was born in 1901. I'm younger than Corey Olsen. If you do the math...that's fewer generations than you might expect. I have a step-great-grandmother. I have a cousin who died in his 20s, leaving behind a widow and 10 year old son. My mom has a sister 16 years older than she is. I am hoping that all of these quirks are the sort of details that would serve the story, not clutter it up, but obviously they might not all fit in very well.
I take it we’re eliminating Bregolas?
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Once I half heartedly suggested we have Barahir be the father of Baragund and Belegund, with Beren as the youngest son. But again we run into the problem that Morwen would be the Chief of the House of Beor (though it’s likely a moot point since the massacre of Tarn Aeluin in F.A. 460).
Not necessarily. It would be possible to make Bregor the father of Beldis, Baragund, and Belegund, eliminating Bregolas. But it isn't required. And I don't think we need to make Baragund and Belegund into Beren's brothers. But yes, it is quite possible that Bregolas will not exist in our version of the story. If Bregor is dying in the Dagor Bragollach, we wouldn't need Bregolas to do so as well.
We were always going to need a story why Barahir, younger brother of Bregolas, became the chieftain/leader of his house, rather than Baragund or Belegund, Bregolas' adult sons. It's the same story if Barahir is Bregor's younger brother, and he becomes leader over his sons Baragund and Belegund. When all three are killed, though, Beren being the heir is the default.