Well...it would seem the Imprisoning War happened sometime before OoT. To back it up, I'll provide this...
"Some time ago, before the King of Hyrule unified this country, there was a fierce war in our world.
One day, to escape from the fires of the war, a Hylian mother and her baby boy entered this forbidden forest.
The mother was gravely injured... Her only choice was to entrust the child to the Deku Tree, the guardian spirit of the forest.
The Deku Tree could sense that this was a child of destiny, whose fate would affect the entire world, so he took him into the forest.
After the mother passed away, the baby was raised as a Kokiri. And now, finally, the day of destiny has come!"
from Oot...and
"In a period known as the Imprisoning War, the King of Hyrule brought seven wise men together to seal the door to the Golden Land, for Ganon's evil power had been spilling forth, causing corruption and darkness. The once peaceful land became a place of dreadful rumors of the coming of a magical enemy. At this time the Master Sword was forged, but there was no hero valiant enough to wield it."
ALttP