HISTORY OF MARINE ARCHITECTURE.

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dominion of the imperial purple, yet the time during which it maintained itsclaim to these newly acquired accessions to its former triumphs *, was so ex-tremely short, that it passes rather like a transient vision before our eyes, than asaffording the substantial image of established rule. Nearly in a state experi-encing neither flux nor reflux, did the empire of Rome continue for the spaceof two hundred years, from the reign of the last of the Caesars, during those ofTrajan, Adrian, the Antonines, and others, to that of Dioclesian. Pendingthis interval, the utmost attention, and every protection the authority of govern-ment was capable of affording commerce, was uniformly paid to it. The portof Ostia, at the entrance of the Tyber, considerably improved under the direc-tion of the emperor Claudius, became, as it were, the grand emporium oftraffic for every part of the world then known. Its contiguity to Rome, fromwhich it is only sixteen miles distant, and its centrical situation in respect tothe Mediterranean sea, conjunctly raised it, when added to that artificial im-provement which had been exerted to render it commodious, into the highestconsequence.

The trade of the Mediterranean, that is to say, such as was carried on withthe different countries which surrounded it, far exceeded that which existedwith every other country in the world ; for although concurrent testimonyappears to have placed it beyond doubt, that a traffic was carried on with India,from the port now called Suez, in the Red Sea, and the commodities receivedfrom thence being conveyed over land to the Nile, became transported, withoutmuch difficulty, to Rome, which thus acquired the opportunity of adding to herformer luxuries all the natural as well as artificial productions of the east.This traffic was, however, extremely limited, not only on account of its beingtedious, difficult, and dangerous, but because it drained Rome, the capital, ofspecie, in which alone the returns were made for commodities purchased, andfor that reason soon became highly unpopular.

From the death of Commodus to the reign of Dioclesian, the empire wasoccasionally convulsed by the civil commotions created between the rival com-petitors for the imperial throne ; but the limits of the empire continued exactlythe same. The intestine wars were entirely carried on between the legionarytroops of different provinces supporting the cause of those who had been re-spectively elected by them to fill the dignity of emperor, or the native armies of

* Mesopotamia, Armenia, and other countries, were voluntarily abandoned by Adrian, the successorto Trajan.

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