Still however, some difficult questions remain to be considered. In the first place, it is evident that whatever commerce was carried on by Laconia,(981) could not have existed without a coinage of universal currency. Now it is impossible that this trade could have been carried on by the state, since it would have required a proportionate number of public officers; consequently it was in the hands of the Periœci. We must therefore suppose that the possession of silver coin was allowed to this class of persons; in general, indeed the Spartan customs did not without exception extend to the Periœci. Nor could this have had much influence upon the Spartans, since they had not any personal connexion with the Periœci, the latter being only tributary to the state. In the market of Sparta in which the Spartans and Helots sold their corn and the products of native industry were exposed, all foreigners being entirely excluded,(982) doubtless none but the iron coin was used; and so also in the whole of Laconia it was current at its fixed value; but those Lacedæmonians who were not of Doric origin must have possessed a currency of their own, probably under certain restrictions. And the tributes of these persons were doubtless the chief source from which the state derived its silver and gold coins. Besides this, the kings must also have been privileged to possess silver and gold. If some permission of this kind had not existed, Pausanias (who was in strictness only guardian of the king) would not have been able to receive among other spoils ten talents from the plunder of Platæa;(983) and Pleistonax and Agis the First could not have been fined in the sums of fifteen talents, and 100,000 drachmas:(984) at a later time also, as has been already remarked, Agis the Third was possessed of six hundred talents.(985) The estates of the kings were also situated in the territory of the Periœci, in which silver money was in circulation, and it is at least possible that the payments may have been made to them in this coinage. Herodotus states that every king at the beginning of his reign remitted all the debts of the citizens both to the state and to the kings:(986) they therefore cancelled all certificates of debt, which in Sparta were called κλάρια, or mortgages, probably because the land (and in early times the produce of the land only) was assigned as security.(987) This was a wise institution, by which those persons in particular were relieved who had, for a particular object, received from the kings or the state, gold or silver, which on account of the small value of the iron coinage they were seldom able to repay. Now gold and silver were, for example, necessary to all persons who had to undertake a journey out of Laconia, and these they could not obtain otherwise than from the magistrates or the king,(988) a measure which must have placed great obstacles in the way of foreign travel.