of kingdoms:  the countries over which the dominant state acquires an influence, not only retain their distinct individuality, as is the case in some modern empires, but remain in all respects such as they were before, with the simple addition of certain obligations contracted towards the paramount authority.  They keep their old laws, their old religion, their line of kings, their law of succession, their whole internal organization and machinery; they only acknowledge an external suzerainty which binds them to the performance of certain duties towards the Head of the Empire.  These duties, as understood in the earliest times, may be summed up in the two words “homage” and “tribute;” the subject kings “serve” and “bring presents.”  They are bound to acts of submission; must attend the court of their suzerain when summoned, unless they have a reasonable excuse; must there salute him as a superior, and otherwise acknowledge his rank; above all, they must pay him regularly the fixed tribute which has been imposed upon them at the time of their submission or subjection, the unauthorized withholding of which is open and avowed rebellion.  Finally, they must allow his troops free passage through their dominions, and must oppose any attempt at invasion by way of their country on the part of his enemies.  Such are the earliest and most essential obligations on the part of the subject states in an empire of the primitive type like that of Assyria; and these obligations, with the corresponding one on the part of the dominant power of the protection of its dependants against foreign foes, appear to have constituted the sole links which joined together in one the heterogeneous materials of which that empire consisted.

It is evident that a government of the character here described contains within it elements of constant disunion and disorder.  Under favorable circumstances, with an active and energetic prince upon the throne, there is an appearance of strength, and a realization of much magnificence and grandeur.  The subject monarchs pay annually their due share of “the regulated tribute of the empire;” and the better to secure the favor of their common sovereign, add to it presents, consisting of the choicest productions of their respective kingdoms.  The material resources of the different countries are placed at the disposal of the dominant power; and skilled workmen are readily lent for the service of the court, who adorn or build the temples and the royal residences, and transplant the luxuries and refinements of their several states to the imperial capital.  But no sooner does any untoward event occur, as a disastrous expedition, a foreign attack, a domestic conspiracy, or even an untimely and unexpected death of the reigning prince, than the inherent weakness of this sort of government at once displays itself—­the whole fabric of the empire falls asunder—­each kingdom re-asserts its independence—­tribute ceases to be paid—­and the mistress of a hundred