The Earth/Minbari war began as a misunderstanding. The first time a Terran ship encountered a Minbari starship, they studied each other closely. The Minbari ship made a move that they thought would be considered non- threatening. It wasn't. Even in the present of our story, no one is quite sure who fired first. The Minbari ship was greater in power, but taken by surprise, was destroyed, and the Earth ship limped back to base with tales of a terrible new enemy. Minbari ships, arriving to investigate, were interpreted to be the first wing of an invasion force by the base commander, and ships were launched in response before receiving formal authorization from Earth Central.
The war put a great strain on the Minbari, who have always been strongly divided between the religious caste, and the military caste, who were now forced to work together. The religious caste were quietly opposed to the war, but were generally vague about their reasons when asked.
The war went badly for Earth, with one loss after another; the Minbari had an overwhelming technological advantage. During the entire course of the war, Earth scored only one major victory, when a young officer named John Sheridan destroyed the Minbari war cruiser Black Star and several accompanying vessels. It was all downhill from there.
The Battle of the Line, from "And the Sky Full of Stars".
In the course of that battle, a lone ship -- a one-man fighter with very little in the way of armaments -- took several heavy hits. His instruments failing, other ships blowing up all around him, he aimed his ship at the nearest Minbari cruiser, deciding to ram it in the hopes of destroying at least that one ship. He kept his ship on course for as long as he could hold out. Then, abruptly, he blacked out.
When he awoke, he was still in his ship. Drifting. He fired up the engines, ready to continue, only to discover two things: first, that he had been out of it for a full 24 hours.
Second...the war was over.
And, incredibly, the Minbari had surrendered. On the very verge of success in the war, they had rolled over and sued for peace. No one in the Earth Alliance quite knew why, but they weren't about to debate the issue, and accepted minimal compensation for the war.
Now, ten years later, the Earth Alliance is no closer to figuring out why the Minbari surrendered. It is, in fact, one of the great puzzles of that era, debated on a hundred different worlds. Only a few strange clues have slipped out. One is that the military genius who led the Minbari into the war committed suicide the day of the surrender, though it is unclear if his death took place before or after the surrender. And the rift between the military and religious castes apparently came to some sort of climax, with the religious caste taking complete control. There are rumors of some sort of religious vision, of a prophecy of great things, and a prophecy of complete doom. But since almost nothing is known of Minbari religion, what this might be, no one knows.
At the conclusion of the war, those Terrans who fought in the Battle of the Line were proclaimed heroes. One of these men was Jeffrey Sinclair...the pilot who still cannot account for the 24 hours he was out of contact with Earth Central. (cf. "And the Sky Full of Stars")
Commander Jeffrey Sinclair has come far in the 10 years since the war. He's had some rough times, but overall he's progressed. And he has at last been given a major assignment, perhaps the most important job of his life, concomitant with his promotion to Commander.
Command of the newly-built Babylon 5 space station.