The Battle of the Line is a fictional battle in the Babylon 5 fictional universe, it was the final battle of the Earth-Minbari war. The Battle of the Line was a desperate attempt by the Earth Alliance to stop a Minbari combat fleet from attacking Earth. Over 20,000 Human defenders fought in the battle; including most of the remaining warships of the Earth fleet. Despite this armada, the Minbari fleet easily destroyed most of the defending human warships, taking basically no losses themselves. Incredibly, however, the Minbari suddenly surrendered to the almost-defeated humans with no explanation.
The first commander of the Babylon 5 outpost, Earthforce Commander Jeffrey Sinclair, was captured by the Minbari during the battle. One major plot element of the first season of the television show involves his attempts to regain his memory of those events.
Approximately two years before the Battle of the Line, the first contact between Humans and Minbari ended in disaster. The lead Minbari ship opened their gun ports as a show of respect, but the captain of the lead Earth ship, believing this heralded an attack, opened fire pre-emptively. This resulted in the death of Dukhat, one of the nine members of the "Grey Council" who rule the Minbari species. The Grey Council, offended, declared a holy war against the humans. Dukhat's protégé, Delenn, cast the deciding vote.
The resulting conflict was essentially one-sided, as the Minbari were far more technologically advanced than the humans; their weapons were better and their defenses so powerful that most human pilots and weapons officers could not even achieve firing solutions. Additionally, the Minbari gave no quarter. The result was a bitter war in which the Earth Alliance military bought time with their lives. Commander John Sheridan succeeded in destroying the Black Star, the Minbari flagship—it was the only Minbari capital ship lost during the entire war, and it was ultimately a fruitless victory.