Once appointed, the tax-gatherers were directed by the "chief-of-men." The tribute was chiefly maize, but might be anything the conquerors chose to demand,--weapons, fine pottery or featherwork, gold ornaments, or female slaves. Sometimes the tributary pueblo, instead of sacrificing all its prisoners of war upon its own altars, sent some of them up to Mexico as part of its tribute. The ravening maw of the horrible deities was thus appeased, not by the pueblo that paid the blackmail, but by the power that extorted it, and thus the latter obtained a larger share of divine favour. Generally the unhappy prisoners were forced to carry the corn and other articles. They were convoyed by couriers who saw that everything was properly delivered at the _tecpan_, and also brought information by word of mouth and by picture-writing from the _calpixqui_ to the "chief-of-men." When the newly-arrived Spaniards saw these couriers coming and going they fancied that they were "ambassadors." This system of tribute-taking made it necessary to build roads, and this in turn facilitated, not only military operations, but trade, which had already made some progress albeit of a simple sort. These "roads" might perhaps more properly be called Indian trails,[127] but they served their purpose. [Footnote 127: See Salmeron's letter of August 13, 1531, to the Council of the Indies, cited in Bandelier, _op. cit._ p. 696. The letter recommends that to increase the security of the Spanish hold upon the country the roads should be made practicable for beasts and wagons. They were narrow paths running straight ahead up hill and down dale, sometimes crossing narrow ravines upon heavy stone culverts.] [Sidenote: Aztec and Iroquois confederacies contrasted.]