Vad hände med Babylon-4 efter kriget mellan Shadows och Minbari slutade för tusen år sedan?

Detta förklarades i den begränsade serien "In Valen's Name" i Babylon 5, skrivet av JMS (och Peter David) så definitivt kanon.

Delenn reveals that after the last Shadow War, Babylon 4 was taken to a place of rest, its final location a secret. The crew who took it there never returned. Its fate was a mystery for nine hundred years -- until now.

http://www.midwinter.com/lurk/comic/012.html

Jag kan inte hitta min kopia av serien men här är vad en B5 fan wiki säger om slutsatsen:

For over 900 years the station lay dormant, guarded by the Tak'cha, who referred to it as Ende X'Ton ("the lost station") which they believed to be a holy place. In 2261 it was found floating adrift in Sector 730 by 12 by 9 by John Sheridan, Delenn, Michael Garibaldi, and Susan Ivanova. Within 48 hours of rediscovering the station, Babylon 4 burned up in the atmosphere of the planet it was orbiting.

http://babylon5.wikia.com/wiki/Babylon_4