I've figured out that Morrowind begins on the 16th of Last Seed and that it starts just a few years before Oblivion begins, so its around the 3E429 mark, but I can't figure out what year it begins precisely.

Can anyone help me?

I want to say 3E 427. But I'm not quite sure.

3E 427
-The events of The Elder Scrolls III: Morrowind take place.
-The Nerevarine is discovered, and at the same time the Prophecy of the Nerevarine is revealed to be true.
-The Nerevarine contracted Corprus, and was cured by Divayth Fyr.
-The Nerevarine reclaimed the Moon-and-Star from Azura, proving himself to be the true Incarnate of Nerevar.
-The Nerevarine became the Hortator and united all three Great Houses to oppose Dagoth Ur.
-The Ghostfence ceased to exist.
-Dagoth Ur is killed at Red Mountain by the Nerevarine.

3E 428
-The events of The Elder Scrolls III: Tribunal take place.
-The Nerevarine reclaimed the Trueflame as his weapon.
-Sotha Sil is betrayed and killed by Almalexia.
-Almalexia is killed by the Nerevarine in self-defence.

3E427