This insertion was probably so arranged that, while each tribe and wardship received its assigned proportion of the new burgesses, the new burgesses in these divisions were not amalgamated completely with the old; the tribes henceforth presented two ranks: the Tities, Ramnes, and Luceres being respectively subdivided into first and second (-priores-, -posteriores-).

With this division was connected in all probability that arrangement of the organic institutions of the community in pairs, which meets us everywhere.

The three pairs of Sacred Virgins are expressly described as representatives of the three tribes with their first and second ranks; and it may be conjectured that the pair of Lares worshipped in each street had a similar origin.

This arrangement is especially apparent in the army: after the union each half-tribe of the tripartite community furnished a hundred horsemen, and the Roman burgess cavalry was thus raised to six "hundreds," and the number of its captains probably from three to six.

There is no tradition of any corresponding increase to the infantry; but to this origin we may refer the subsequent custom of calling out the legions regularly two by two, and this doubling of the levy probably led to the rule of having not three, as was perhaps originally the case, but six leaders-of-division to command the legion.