During the vigor of his age, Constantine, according to the various exigencies of peace and war, moved with slow dignity, or with active diligence, along the frontiers of his extensive dominions, and was always prepared to take the field either against a foreign or a domestic enemy. But as he gradually reached the summit of prosperity and the decline of life, he began to meditate the design of fixing in a more permanent station the strength as well as majesty of the throne. In the choice of an advantageous situation, he preferred the confines of Europe and Asia; to curb with a powerful arm the barbarians who dwelt between the Danube and the Tanais; to watch with an eye of jealousy the conduct of the Persian monarch, who indignantly supported the yoke of an ignominious treaty. With these views, Diocletian had selected and embellished the residence of Nicomedia: but the memory of Diocletian was justly abhorred by the protector of the Church; and Constantine was not insensible to the ambition of founding a city which might perpetuate the glory of his own name. During the late operations of the war against Licinius, he had sufficient opportunity to contemplate, both as a soldier and as a statesman, the incomparable position of Byzantium, and to observe how strongly it was guarded by nature against a hostile attack, while it was accessible on every side to the benefits of commercial intercourse.
Many ages before Constantine, one of the most judicious historians of antiquity had described the advantages of a situation, from whence a feeble colony of Greeks derived the command of the sea and the honors of a flourishing and independent republic.[50]
The harbor of Constantinople, which may be considered as an arm of the Bosporus, obtained, in a very remote period, the denomination of the "Golden Horn." The curve which it describes might be compared to the horn of a stag, or as it should seem, with more propriety, to that of an ox. The epithet of golden was expressive of the riches which every wind wafted from the most distant countries into the secure and capacious port of Constantinople. The river Lycus, formed by the conflux of two little streams, pours into the harbor a perpetual supply of fresh water, which serves to cleanse the bottom and to invite the periodical shoals of fish to seek their retreat in that convenient recess. As the vicissitudes of tides are scarcely felt in those seas, the constant depth of the harbor allows goods to be landed on the quays without the assistance of boats; and it has been observed that in many places the largest vessels may rest their prows against the houses, while their sterns are floating in the water. From the mouth of the Lycus to that of the harbor, this arm of the Bosporus is more than seven miles in length. The entrance is about five hundred yards broad, and a strong chain could be occasionally thrown across it, to guard the port and city from the attack of a hostile navy.
The geographers who, with the most skilful accuracy, have surveyed the form and extent of the Hellespont, assign about sixty miles for the winding course, and about three miles for the ordinary breadth, of those celebrated straits. But the narrowest part of the channel is found to the northward of the old Turkish castles between the cities of Sestus and Abydus. It was here that the adventurous Leander braved the passage of the flood for the possession of his mistress.[51] It was here likewise, in a place where the distance between the opposite banks cannot exceed five hundred paces, that Xerxes imposed a stupendous bridge of boats, for the purpose of transporting into Europe a hundred and seventy myriads of barbarians. A sea contracted within such narrow limits may seem but ill to deserve the singular epithet of broad, which Homer, as well as Orpheus, has frequently bestowed on the Hellespont. But our ideas of greatness are of a relative nature: the traveller, and especially the poet, who sailed along the Hellespont, who pursued the windings of the stream, and contemplated the rural scenery, which appeared on every side to terminate the prospect, insensibly lost the remembrance of the sea: and his fancy painted those celebrated straits, with all the attributes of a mighty river flowing with a swift current, in the midst of a woody and inland country, and at length, through a wide mouth, discharging itself into the Ægean or Archipelago.
Ancient Troy, seated on an eminence at the foot of Mount Ida, overlooked the mouth of the Hellespont, which scarcely received an accession of waters from the tribute of those immortal rivulets, the Simois and Scamander. The Grecian camp had stretched twelve miles along the shore from the Sigæan to the Rhætean promontory; and the flanks of the army were guarded by the bravest chiefs who fought under the banners of Agamemnon.
The first of those promontories was occupied by Achilles with his invincible myrmidons, and the dauntless Ajax pitched his tents on the other. After Ajax had fallen a sacrifice to his disappointed pride and to the ingratitude of the Greeks, his sepulchre was erected on the ground where he had defended the navy against the rage of Jove and of Hector; and the citizens of the rising town of Rhæteum celebrated his memory with divine honors. Before Constantine gave a just preference to the situation of Byzantium, he had conceived the design of erecting the seat of empire on this celebrated spot, from whence the Romans derived their fabulous origin. The extensive plain which lies below ancient Troy, toward the Rhætean promontory and the tomb of Ajax, was first chosen for his new capital; and though the undertaking was soon relinquished, the stately remains of unfinished walls and towers attracted the notice of all who sailed through the straits of the Hellespont.
We are at present qualified to view the advantageous position of Constantinople; which appears to have been formed by nature for the centre and capital of a great monarchy. Situated in the forty-first degree of latitude, the imperial city commanded, from her seven hills, the opposite shores of Europe and Asia; the climate was healthy and temperate, the soil fertile, the harbor secure and capacious; and the approach on the side of the Continent was of small extent and easy defence. The Bosporus and the Hellespont may be considered as the two gates of Constantinople; and the prince who possessed these important passages could always shut them against a naval enemy and open them to the fleets of commerce. The preservation of the eastern provinces may, in some degree, be ascribed to the policy of Constantine, as the barbarians of the Euxine, who in the preceding age had poured their armaments into the heart of the Mediterranean, soon desisted from the exercise of piracy and despaired of forcing this insurmountable barrier.
When the gates of the Hellespont and Bosporus were shut, the capital still enjoyed within their spacious enclosure every production which could supply the wants or gratify the luxury of its numerous inhabitants. The sea-coasts of Thrace and Bithynia, which languish under the weight of Turkish oppression, still exhibit a rich prospect of vineyards, of gardens, and of plentiful harvests; and the Propontis has ever been renowned for an inexhaustible store of the most exquisite fish, that are taken in their stated seasons, without skill and almost without labor. But when the passages of the straits were thrown open for trade, they alternately admitted the natural and artificial riches of the north and south, of the Euxine, and of the Mediterranean. Whatever rude commodities were collected in the forests of Germany and Scythia, as far as the sources of the Tanais and the Borysthenes; whatsoever was manufactured by the skill of Europe or Asia; the corn of Egypt, and the gems and spices of the farthest India, were brought by the varying winds into the port of Constantinople, which for many ages attracted the commerce of the ancient world.
The prospect of beauty, of safety, and of wealth, united in a single spot, was sufficient to justify the choice of Constantine. But as some decent mixture of prodigy and fable has, in every age, been supposed to reflect a becoming majesty on the origin of great cities, the Emperor was desirous of ascribing his resolution, not so much to the uncertain counsels of human policy as to the infallible and eternal decrees of divine wisdom. In one of his laws he has been careful to instruct posterity that, in obedience to the commands of God, he laid the everlasting foundations of Constantinople: and though he has not condescended to relate in what manner the celestial inspiration was communicated to his mind, the defect of his modest silence has been liberally supplied by the ingenuity of succeeding writers, who describe the nocturnal vision which appeared to the fancy of Constantine, as he slept within the walls of Byzantium. The tutelar genius of the city, a venerable matron sinking under the weight of years and infirmities, was suddenly transformed into a blooming maid, whom his own hands adorned with all the symbols of imperial greatness. The monarch awoke, interpreted the auspicious omen, and obeyed, without hesitation, the will of heaven.