Armistice Line

The Armistice Line is a border between Cylon and Colonial territories, likely drawn out during the Cimtar Peace Accords.

One year prior to the Fall of the Twelve Colonies, Commander William Adama of battlestar Valkyrie was ordered by Admiral Corman on a secret mission to recon the Cylon's space to determine their potential military operations. To do so, Adama sent Lieutenant Daniel Novacek in a Stealth Star over the Armistice Line, where Novachek was intercepted by a lone Cylon contact.

In a vain attempt to cover up the trespass, Adama sent a ship-to-ship missle to Novacek's location. The Cylons summarily captured Novacek, who ejected from the craft prior to its destruction.

Up until the time of Novacek's return after the Second Exodus, Adama believes that this trespass lead to the Cylon attack against the Colonies (Hero).

It's likely that cylon agents had been violating the armistice line for some time prior to Adama's transgression.