Of the several impositions introduced by Augustus the five per cent. on legacies and inheritances was the most fruitful as well as the most comprehensive. Farmed like nearly all other taxes (for in every age the best and wisest of the Roman governors adhered to this pernicious method of collecting the principal customs), the burden was increased by the insolence and cupidity of the collectors; hence, when two centuries afterwards Caracalla doubled the already heavy impost, this act of oppression nearly cost him his throne and his life.[307] Yet, in spite of the extravagant luxury of the wealthier classes, the enormous value of the imperial commerce, together with the extent and wealth of the provinces, enabled the government to maintain for a long time an expenditure which, under other circumstances, could not have been endured; and much, indeed, of this wealth was really due to the possession of Egypt, apart altogether from the large commercial profits derived from Alexandria. Besides corn, Egypt supplied the imperial city with flax and linen of various qualities, cotton goods, costly ointments, marble, alabaster, fine alum, salt, gums, and the papyrus, from which paper was manufactured at Rome. Three hundred thousand of the million inhabitants of Alexandria consisted of Roman citizens, but its merchants and ship-owners were chiefly emigrants from Greece or of Grecian origin. [Sidenote: Its extent.] Although the value of the trade with Egypt, which comprised the chief portion of that with India and Arabia, was in itself greater than any other, it fell far short of supplying the numerous wants of Rome. Caravans traversed, as they had done centuries before that city became mistress of the world, the whole latitude of Asia in two hundred and forty-three days,[308] from the Chinese ocean to the sea coast of Syria, to supply her with the silk her rich citizens were always eager to obtain. Nor could Egypt alone supply her demands even for corn and cattle. That fertile country, which stretches from the southern foot of the Alps to the shores of the Mediterranean, grew large quantities of corn for Rome, and reared numerous cattle for her market, while from Northern Italy she drew her supplies of salt provisions for the use of her troops and mariners. The Sabine country also furnished wheat, rice, and barley; and thence large quantities of wine were imported, as well as from Corsica, Sardinia, and Sicily. Timber, suitable for ship-building purposes, was extensively imported from Etruria. Genoa exported largely, for the use of the Romans, wood for furniture, coarse wool for the clothing of their slaves, hides, and honey.