A battle was the decisive moment of a military expedition. Because of this battles are by far the most frequently recorded type of engagement in the historical records. It is likely that many more military expeditions did not culminate in any decisive action and were therefore not recorded. The decisive nature of battles meant they were a high risk option; the defeated force risked annihilation if they did not have a line of retreat to a defensive position. Battles, therefore, would only tend to occur when either the opposing forces were, or mistakenly believed themselves to be, of a similar size or, when a weaker force was caught by a fast moving enemy and forced to fight.