although mints were established in various places, a commercial treaty between Stephen, Banus of Bosnia, and Ragusa alludes to the fact that cattle were used for payments of indemnities.[257] Communications between Ragusa and the settlements in the interior were carried on by means of couriers (_cursores_, _corrieri_, Slav. _knižnici_), who were instituted early in the fourteenth century, and lasted until the fall of the Republic. They carried official correspondence from the Republic to the ambassadors and consuls, and legal notices, writs, reports of judicial proceedings, &c., to the Ragusan traders. They were not allowed to convey private correspondence, which was usually sent by caravan, or in the case of the chief merchants by their own special messengers, save on the return journey. The time employed by these official messengers was usually two days from Ragusa to Blagaj (Mostar), four or five to Visoko or Sutieska, five or six to Prača, seven or eight to Srebrnica, ten to Zvornik, twelve to Syrmium, seven to Rudnik or Novobrdo, fifteen to Constantinople. In bad weather, when the passes were blocked with snow, double the time was often necessary to traverse the same distance, which was the time required by the caravans in favourable weather. The envoys sent to Constantinople with the tribute to the Sultan took as much as two months.[258] The official correspondence to the various Ragusan representatives in the East is preserved in the archives of Ragusa in 138 volumes, under the heading of _Lettere e Commissioni di Levante_.