This is a list of French ships of the line of the period 1621–1870 (plus some from the period before 1621). Battlefleet units in the French Navy (Marine Royale before the French revolution established a republic) were categorised as vaisseaux (literally "vessels") as distinguished from lesser warships such as frigates (frégates). The vaisseaux were classified according to size and/or firepower into a series of Rangs (ranks), roughly equivalent to the system of Rates used by the British Navy, although these did not correspond exactly. By 1671 there was a system of five Rangs, which officially pertained for over a century; the first three of these Rangs comprised the battlefleet vaisseaux, while the Fourth and Fifth Rangs comprised the larger frigates ("frégates-vaisseaux" or simply "frégate