The Seven Years’ War (1756–63) marked the definite adoption of the term frigate for a class of vessel that was smaller than the three-decked ship of the line but was still capable of considerable firepower. A frigate was a three-masted, fully rigged vessel, with its armament carried on a single gun deck and with additional guns on the poop and forecastle. The number of guns varied between 24 and 56, but 30 to 40 guns were common. Frigates could not stand up to ships of the line in fleet engagements, but, sailing at greater speed, they served as scouts or as escorts protecting merchant convoys from privateers and enemy raiders; they also cruised the seas as merchant raiders themselves.