In the primordies of DDO, the quests chronological order were set up to be in the order they were added to the game. So, even if a specific quest was actually lower level than Vault of Night, it was being "done" later in time.
With the addition of Chronoscope, that rule was dropped, and now the quest timeline is linear with quest level. Every level 8 quest now "happens" before any other level 9 quest in game. And until MotU, there was no "epic" quest on itself, but only epic versions of other quests. So, we know that even if TTT was endgame, chronologically speaking, it was a level 7 quest and the storyline fit there.
Then we get Shadowfell Conspiracy.
The expansion was being advertised as a pack with level 16 and 19 quests. However the quest storyline makes reference to the drow invasion that we fight at level 21-22. Ok. This can be explained by those quests being actually the contrary of the other quests with heroic and epic versions, with them being primarly epic, with an heroic version. This would fit the quest storyline, with the chains being upgraded to level 26 and 27.
However, we got heroic High Road in the same time. And the prequel quests are still heroic only. This would not fit with the Wheloon storyline if it was considered epic only. And Storm Horns storyline mention an attack from Wheloon at the same time.
So, considering the Heroic line, the history proceed as this:
- Shadowfell pre-quests (U18)
- Web of Chaos (U13)
- Wheloon chain (Simultanously with U13, but it comes first by being added to game first)
- Druid'd Deep (U15)
- High Road (U16)
- Storm Horns chain
But if we consider FR to be primarly an epic story lines, with Heroic versions, things goes as this:
- Shadowfell pre-quests (U18, Level 15)
- Web of Chaos (U13, Level 21)
- King's Forest chain (MotU, Level 21)
- Sschindylryn chain (MotU, Level 22)
- Demonweb chain (MotU, Level 23)
- Druid'd Deep (Level 23, simultaneous with Demonweb chain)
- CitW (Level 24)
- High Road (Level 24)
- Wheloon chain (Level 26)
- Storm Horns chain (Level 27)
Which one is the correct chronological line? Or is something else?
EDIT: Created a new topic on the quest sub-forum. If you find this post in the future, please, comment there.