New Rome -- Constantine and Constantinople
The official grand opening of Constantine's new capital, which, with typical imperial modesty, he had named after himself, was on May 11, 330 AD. There had, of course, been centuries of history on the site before the Roman "founder" arrived.
Already in ancient times, there were several long established founding myths that purported to explain the origin of the city, but those most often told revolved around Byzas and his family. The oldest versions of the Byzas stories have him as a Thracian king some time between 600 and 800 BC. There always had to be a mythical connection, so he was said to have been the son of the nymph Semestra. Byzas marries Phidaleia, the daughter of a local king, Barbyzos, and Phidaleia founds a new city, naming it Byzantion after both her husband and her father.
The mythical connections later grew thicker and involved the major players in the Greek pantheon: that notorious rake, Zeus, had a fling with Io, and Hera, his wife, as usual, was sorely displeased. Io escaped Hera's wrath by changing herself into a cow and wandering away -- the path of her wandering was the Bosporus, which can mean "cow path" in Greek but is interpreted now, more pompously, as "Strait of the Cow". Along her route, she gave birth to Zeus's child, a daughter named Keroessa, who was raised by Semestra. On reaching maturity, Keroessa had a child with the sea god, Poseidon. The child, raised by the nymph Byzia, was known as Byzas, and he's that same Thracian king mentioned above. There's a bit more of this nonsense at http://www.boun.edu.tr/istanbul/history.html.
The oldest archeological evidence at the site of the city dates only from the end of the 4th century BC. But just a few miles away, there are caves with stone-age remains. Most of Istanbul has never been excavated with modern archeological methods, and it's probable that there are habitation layers beneath the city that haven't been uncovered. The present city site has certainly always been the best location for a settlement, and it's likely that the earliest folks arriving in the area it would have claimed it. Excavations in 1937 in the "Second Courtyard" of Topkapi Palace turned up some 7th century BC artifacts, but they came from a filled-in area, to which soil brought in from some other unknown site had been added.
Its clear that there was a full-blown Hellenic city on the site long before the first Romans showed their faces in the east, and, as usual, it was an "acropolis" or "hilltop city". By the 2nd century BC it had high walls and was wealthy from the revenues of its fishing fleets and the taxes it levied on transport ships moving between the Black Sea and the Mediterranean (the latter of which, by the way, was then called the "White Sea" -- the "Red Sea" was where it still is, and the Atlantic was the "Blue Sea"). For a long time, even after the arrival of the Romans and their eventual dominance of the whole of the Mediterranean basin, Byzantion (Byzantium in Latin) was nominally independent.
But inevitably Byzantium got caught up in local battles among Roman generals aspiring to be Emperors, and the city became just another Roman pawn. Its bad choices in Roman dynastic battles finally led, in 196 AD, to the wholesale slaughter of the city's civic administrators and warriors and to the destruction of its city walls. It was then officially deprived of its official status as a Roman city and was bound as a subsidiary "village" to nearby Perinthos. Emperor Septimius Severus rather rapidly returned it to its previous "city" status in the early 3rd century AD, but he kept it as a private domain and renamed it Antonina after his own "Antonine" dynasty. He and later emperors built impressive structures in Byzantium, as they also still did in other parts of the Empire, and it is to this period that the last "Roman" monuments date (as opposed to "Byzantine" stuff that came after Constantine.)
Antonina lasted only until a new imperial succession crisis began with the abdication of Diocletian in 305 AD. Diocletian was a well-intentioned reformer trying to swim against an overwhelming tide of barbarian and internal military opportunism. To make the burden of rule more manageable, he had split the empire into four administrative entities under two "Caesars" and two "Augusti" (junior rulers), and it worked pretty well as long as Diocletian was the senior Caesar. In 305, after 21 years of rule, he put his reforms to the ultimate test by abdicating and forcing his co-Caesar, Maximian, to do the same. Constantius and Galerius, the two former Augusti, became the new Caesars, and Maximinus and Severus were named to replace them as Augusti.
Everything immediately fell apart, and it wasn't put back together until Constantine, the son of Constantius, defeated Maxentius, the son of the former Caesar Maximian in 312 AD. For more information on Diocletian and his reforms, go to http://www.roman-emperors.org/dioclet.htm, and for details of the battles among the Caesars and Augusti and their sons, see http://www.roman-emperors.org/conniei.htm. During all these battles, the cities of the empire were again caught in the crossfire, and Antonina, like other prized cities, was severely damaged. Although Constantine "won" in 312 AD, he wasn't able to control the east until much later. Well into the 320's, Antonina was still changing hands as alliances shifted and battles were fought. The fog of war eventually lifted and Constantine was the only emperor left standing -- and Antonina was in ruins.
Constantine's immediate problem, of course, was the same one that Diocletian had recognized and tried to solve by splitting the Empire. The empire was too big: Rome was too far west, and the most ominous threats to unity and survival were then in the east. Constantine didn't so much abandon Rome as move his headquarters closer to where the trouble was. At first, according to his own historians, he considered building his base at already ancient Troy: a plausible historical link was the supposed founding of Rome by descendants of Trojan Aeneas. He also may have considered other sites, but eventually the already established (but badly damaged) fortress on the Bosporus was his choice.
Antonina was close to that fractious eastern border of the empire, and, when repaired, it could form a suitable redoubt against the Sasani and others from beyond the fringe. And the city sat on the intersection of land and sea trade routes that would have to be defended even if Antonina weren't the metropolis. By making it his capital, Constantine would concentrate more forces at the one location rather than splitting them between a capital and a trade entrepot.
There were also, of course, politico-religious considerations. Rome was a roiling center of dynastic and aristocratic intrigues, which would be well left behind when Constantine settled his loyalists around a new center. Rivals would have a hard time following him, because the bases of Rome's important families were "latifundia", vast and productive Italian-peninsula agricultural agglomerations peopled with loyal veterans of previous wars. These estates, of course, and the power and wealth they generated, weren't portable. Furthermore, Constantine had already had his "conversion experience". Although his adherence to Christianity hasn't been completely convincing to later historians, it certainly withered support for him in the still solidly pagan -- old pagan and "mystery religion" pagan -- Rome of his time. All in all, his move to a new capital was well advised.
He began to build his new "Constantinopolis" on the ruins of Antonina in 325 AD. Foundations for new, more expansive city walls were laid on November 26, 328: legend has it that an angel told Constantine just where to site his massive new defensive gates. And eighteen months later, there was that impressive ritual inauguration and opening-day of the city. The "inauguration" was the interpretation of the avian flight by bird-watching priests called "augurs" (or "avigurs"). Other rituals made up the actual dedication.
Constantine and his successors enriched and embellished Constantinople for centuries, and, until the Western Empire ended ingloriously with its last emperor, Romulus Augustulus, they also exercised almost unbroken hegemony over that far end of the Mediterranean basin. The urban population of Rome, the old capital, rapidly decreased to a low point in the "dark ages" -- dark for Rome, at least -- of about ten thousand, and it didn't recover to its former size until the 20th century.
Constantinople, meanwhile, flourished through the "Roman period" and the early centuries of the "Byzantine period" -- yes, it's strange that the "Byzantine period" that historians and art connoisseurs always talk about didn't really start until long after Byzantium had ended. Nea Roma ("New Rome" in Greek -- what many local folks called the city despite its official name of Constantinople) officials and potentates had both Greek and Roman titles. Roman style civic structures, shrines, forums, roads, and water works (aqueducts in, cisterns to hold it, and sewers out) proliferated. Churches were built for the Christians, and the remains of some of the greater ones are still prominently to be seen: Justinian's St. Irene as a concert and exhibition hall in the Topkapi "First Courtyard"; his rebuilding of Hagia Sophia on its own grounds, embellished with minarets from its time as a mosque, and now a museum of its own Christian and Muslim art and architecture; and others. Theodosius 2 in an early 5th century urban expansion built the city walls that you can see today.
Eventually the city declined, and by the 11th century the "Great Palace of the Emperors" had become almost a ruin. There were new palaces, but not on the same scale. The hinterlands were taken over by barbarians -- Avars, Huns and the Bulgars sequentially camped right below the city walls -- and the city had to revert to the use of collected rainwater after the aqueducts were cut. Inside the city, intrigues and coups among branches of the ruling families made the city vulnerable.
The final straw for the Byzantine period and Constantinople was the invasion by those barbarian hordes from the West, the Crusaders, who really were just mobs of urban and peasant rabble led by priests and by, mostly, second sons of noble families seeking souls and land respectively. They were supposed to fight the Moslems in the Levant, but the Fourth Crusade (which was financed and transported by the Venetians) stopped at Constantinople to rape, loot, and pillage their fellow Christians. Geoffroy de Villehardouin, a French knight who was among the perpetrators, wrote a detailed account of the fall of Constantinople to the Crusaders. It's clear that the Crusaders entered the city in 1204 on the pretense of defending the rights of Alexius, a young exiled claimant to the Byzantine throne. There were many battles in the city, fires raged, loot was collected and distributed among the victors. The biggest piles of booty found their way back to Venice, where some of the Doge's lot is still proudly displayed in the Cathedral of St. Mark.
Alexis and his rival/brother and all other Byzantine claimants were murdered (by the Crusaders of by each other) or were conveniently "killed in Battle". A Crusader, Baldwin, the Count of Flanders, was then "elected" Emperor by a parliament of nobles -- actually, Baldwin's supporters secured European Constantinople for him, and his chief rival, the Marqis Boniface of Montferrat, got the Asian side of the Bosporus. The Doge was paid off -- 50 thousand silver coins and all the loot he could steal, and he went home well satisfied. If you want to read all the sordid details of the betrayals of and among the Byzantines and then among the Crusader "Franks", a full text translation of Villhardouin's book is on line at http://www.fordham.edu/halsall/basis/villehardouin.html
After fifty years of crusader rule -- that was all it took to strip anything of value from the city -- Constantinople in 1261 was only lightly inhabited rubble. The Genoese helped a final Byzantine dynasty to reclaim the eastern throne, but there never was any real Byzantine revival. The Genoese siphoned off the meager Bosporus customs revenues, which they even had to collect themselves, but they eventually left all but the Galata area, north of the Golden Horn, and Constantinople continued to fall into ruins. Galata remained as a Genoese colony and stayed neutral when the Turks arrived and took over the ruins of Constantinople in 1453. The last ghost of New Rome was long gone from Constantinople.
The above account, of course, hits only a few of the highest waves and plumbs the deepest troughs of the ocean of Istanbul's "Roman" history. And it stops just when the city's greatest flowering, as Istanbul under the Ottomans, is about to begin. But I do Roman stuff -- you can find a very good short survey of the Turkish period at http://www.boun.edu.tr/istanbul/history.html#turk. The same web page, provided by Bogazici University in Istanbul, also goes into greater detail on some of the information covered above -- just scroll up to the top of that page.
There are millions of Internet sites (really!) that deal with Byzantium/Antonina/Constantinople/Istanbul. Just enter one of the names in the Google search engine -- http://www.google.com to find them. Some of those that I used for this article are:
On Constantine: http://www.roman-emperors.org/conniei.htm
On Diocletian: http://www.roman-emperors.org/dioclet.htm
History of the city (Bogazici U, Istanbul): http://www.boun.edu.tr/istanbul/history.html. (For a short history of Bogazici University, which started out in 1863 as Robert College, the first US institution of higher education outside the US borders, go to http://members.tripod.com/~bhaznedar/bogazici/.)
Turkish Ministry of Culture: http://www.kultur.gov.tr/portal/default_en.asp
General info on the city: http://www.guideistanbul.net/tablo1a.htm
Istanbul City Guide: http://www.istanbulcityguide.com/history/
Encyclopedia Britannica: http://www.britannica.com/eb/article?eu=109509&tocid=0&query=istanbul (subscription necessary to access this web page)
P.S.: Istanbul is an easy trip from Rome. Flights are available daily and can be arranged at any travel agency. Hotels and food are very cheap by Rome standards. Shopping is cheap and the range of stuff for sale is enormous: we had to buy an extra one of those big rolling suitcases just to get our purchase back to Rome. Shop in the "Grand Bazaar". It advertises 5,000 shops -- we didn't count them but also didn't doubt the claim. Licensed guides for Istanbul sites ($40 to $50 for two hours) can be arranged through your hotel. The Bosporus Boat Tour (6-7 hours), with a guide and lunches included, was a bargain at $50 per person, and it can also be arranged through your hotel. There are hundreds of good restaurants in all price ranges. We ate big lunches wherever we might be and small hotel dinners. One restaurant not to miss is on the grounds of the Topkapi Palace museum ("Fourth Courtyard"). Get to the Museum as early as you can after it opens in the morning (9:30 AM), hire a guide ($50 for two hours), and right away have the guide make a restaurant reservation for you so you can get a good table for a sit-down lunch overlooking the Bosporus. Evening Belly Dancer shows are widely advertised, but we didn't sample them -- not to our taste.
Go to http://www.mmdtkw.org/Veneto2002.html for other articles. An earlier article on Constantinople is at http://www.mmdtkw.org/VConstantinople.html.