[11] Strabo, vii, p. 317; Appian, Illyric. 17; Aristot. Mirab. Ausc. c. 138. For the extreme importance of the trade in salt, as a bond of connection, see the regulations of the Romans when they divided Macedonia into four provinces, with the distinct view of cutting off all connection between one and the other. All _commercium_ and _connubium_ were forbidden between them: the fourth region, whose capital was Pelagonia (and which included all the primitive or Upper Macedonia, east of the range of Pindus and Skardus), was altogether inland, and it was expressly forbidden to draw its salt from the third region, or the country between the Axius and the Peneius; while on the other hand the Illyrian Dardani, situated northward of Upper Macedonia, received express permission to draw _their_ salt from this third or maritime region of Macedonia: the salt was to be conveyed from the Thermaic gulf along the road of the Axius to Stobi in Pæonia, and was there to be sold at a fixed price. The inner or fourth region of Macedonia, which included the modern Bitoglia and Lake Castoria, could easily obtain its salt from the Adriatic, by the communication afterwards so well known as the Roman Egnatian way; but the communication of the Dardani with the Adriatic led through a country of the greatest possible difficulty, and it was probably a great convenience to them to receive their supply from the gulf of Therma by the road along the Vardar (Axius) (Livy, xlv, 29). Compare the route of Grisebach from Salonichi to Scutari, in his Reise durch Rumelien, vol. ii. [12] About the cattle in Illyria, Aristotle, De Mirab. Ausc. c. 128. There is a remarkable passage in Polybius, wherein he treats the importation of slaves as a matter of necessity to Greece (iv, 37). The purchasing of the Thracian slaves in exchange for salt is noticed by Menander.—Θρᾶξ εὐγενὴς εῖ, πρὸς ἄλας ἠγορασμένος: see Proverb. Zenob. ii, 12, and Diogenian, i, 100.