I've viewed various topics and threads about the idea of all the Fire Emblems in one world and I personally like this idea the best and, after seeing references in Awakening, believe this to be likely.
After looking at Othin's timeline, I was inspired to a bit of my own research and come up with my own hypothesis on a one world-one timeline. Now I haven't done too much into this, and I welcome any feedback or opinions, just please be kind about it. I haven't played through all the Fire Emblems so it's very likely I may have missed something, but I do enjoy the storyline the most of the games.
Anyways, here's what I have:
(Note: I'm basing my timeline on the Archanean one)
-5055: The Great Flood
-4255: Mad King's War
Around -4000: Dragon Tribe Golden Age
-3050: Great Purge (Jugdral Saga)
-2742: Jugdral Saga (Actual start of the game)
-1000: The Scouring
Around -20: Elibe Saga
0
600: Archanean/Valencia(Or whatever spelling is accepted) Saga
1600: Holy King
2600: Awakening
And I want to think Magvel takes place somewhere at the end.
First, I wanted to base the timeline off Archanea because 4 (6) games have now taken place in a world that contain the continents of Archanea/Valencia.
Second, most of my information comes from viewing what users like you may have posted here in these forums, my own experience playing, and the timelines on the site itself.
Third, and after viewing Othin's, it didn't make sense to me for the Scouring to occur before the Jugdral Saga and before the "Miracle of Darn", and the Great Purge fit well as an event that both Lehran and Ashunera could sense coming. (Also, the fact that the events of Tellius ended around ~649 and the Great Purge taking place in 449 just seemed perfect)
I can't remember if I had anything else to back up my ideas, so bring on the criticism (constructive hopefully, not destructive)!