A tribute (from Latin tributum, contribution) is wealth, often in kind, that a party gives to another as a sign of respect or, as was often the case in historical contexts, of submission or allegiance. Various ancient states exacted tribute from the rulers of land which the state conquered or otherwise threatened to conquer. In case of alliances, lesser parties may pay tribute to more powerful parties as a sign of allegiance and often in order to finance projects that benefited both parties. To be called "tribute" a recognition by the payer of political submission to the payee is normally required; the large sums, essentially protection money, paid by the later Roman and Byzantine Empires to barbarian peoples to prevent them attacking imperial territory, would not usually be termed "tribute" as the Empire accepted no inferior political position. Payments by a superior political entity to an inferior one, made for various purposes, are described by terms including "subsidy".