How the five ratings were arrayed in battle is unknown. If the front counted a thousand men (milites),[463] the classis comprised four ranks (4000), the second and third ratings one rank each, making in all six ranks of heavy troops (6000).[464] Twenty centuries could be drawn from the two ratings of light troops to complete the eight ranks when needed.[465] But the Romans undoubtedly exercised the same good judgment as the Lacedaemonians in varying their formation to suit the emergency;[466] and for that reason it is wrong to assume the same depth for all occasions or an even depth for any one occasion. The management of long lines one-man deep must have been extremely difficult, if not impossible.[467] The explanation already suggested, that the state supplied the deficiency in equipment,[468] would greatly simplify the case, for there would then exist no need of arraying the census groups in successive lines. Whatever may have been the tactic arrangement, it did not continue long, for soon after the introduction of regular pay, about 400 B.C.,[469] the distinction between the ratings ceased to have an importance for military affairs. IV. _The Question as to the Connection of the Supernumeraries and the Seniors with the Military Centuries_ A number of supernumeraries termed accensi velati accompanied the army. The epithet accensi proves them to have been outside the five ratings, while velati describes them as wearing civilian dress. We are informed by the sources that they carried water and weapons to the fighting men, stepped into the places of the dead and wounded, and acted as servants to the lower officers.[470] These men could not have been organized in centuries,[471] for they were drawn up in the rear behind the light troops; they extended along the entire breadth of the army,[472] and must have greatly exceeded one hundred or even two hundred. The musicians,[473] too, who accompanied the army were not grouped in two centuries, for they were distributed throughout the army.[474] There is no reason for assuming exactly two hundred musicians[475] or exactly two hundred workmen,[476] or for supposing that any of the men of this description were organized in centuries in the army. Reasoning in a similar way in regard to the seniors, we conclude that their organization in centuries could not have belonged to the original Servian system. A military century, as the name indicates, must have contained a hundred men.[477] But in any static population there are three times as many men between seventeen and forty-six as between forty-six and sixty[478]—in Rome there were three times as many juniors as seniors; and as the number of junior and senior centuries was equal, the latter could have contained only about thirty-three each, on the supposition that the whole male population between seventeen and forty-six years was organized in centuries.