Neolithic artifacts, uncovered by archeologists at the beginning of the 21st century, indicate that Istanbul's historic peninsula was settled as far back as the 6th millennium BCE.
That early settlement, important in the spread of the Neolithic Revolution from the Near East to Europe, lasted for almost a millennium before being inundated by rising water levels.
The first human settlement on the Asian side, the Fikirtepe mound, is from the Copper Age period, with artifacts dating from 5500 to 3500 BCE, On the European side, near the point of the peninsula (Sarayburnu), there was a Thracian settlement during the early 1st millennium BCE.
Modern authors have linked it to the Thracian toponym Lygos, mentioned by Pliny the Elder as an earlier name for the site of Byzantium.

The history of the city proper begins around 660 BCE, when Greek settlers from Megara established Byzantium on the European side of the Bosphorus.
The settlers built an acropolis adjacent to the Golden Horn on the site of the early Thracian settlements, fueling the nascent city's economy.
The city experienced a brief period of Persian rule at the turn of the 5th century BCE, but the Greeks recaptured it during the Greco-Persian Wars.
Byzantium then continued as part of the Athenian League and its successor, the Second Athenian League, before gaining independence in 355 BCE.
Long allied with the Romans, Byzantium officially became a part of the Roman Empire in 73 CE.
Byzantium's decision to side with the Roman usurper Pescennius Niger against Emperor Septimius Severus cost it dearly; by the time it surrendered at the end of 195 CE, two years of siege had left the city devastated.
Five years later, Severus began to rebuild Byzantium, and the city regained—and, by some accounts, surpassed—its previous prosperity.
Neolithic artifacts, uncovered by archeologists at the beginning of the 21st century, indicate that Istanbul's historic peninsula was settled as far back as the 6th millennium BCE. That early settlement, important in the spread of the Neolithic Revolution from the Near East to Europe, lasted for almost a millennium before being inundated by rising water levels. The first human settlement on the Asian side, the Fikirtepe mound, is from the Copper Age period, with artifacts dating from 5500 to 3500 BCE, On the European side, near the point of the peninsula (Sarayburnu), there was a Thracian settlement during the early 1st millennium BCE. Modern authors have linked it to the Thracian toponym Lygos, mentioned by Pliny the Elder as an earlier name for the site of Byzantium.
The history of the city proper begins around 660 BCE, when Greek settlers from Megara established Byzantium on the European side of the Bosphorus. The settlers built an acropolis adjacent to the Golden Horn on the site of the early Thracian settlements, fueling the nascent city's economy. The city experienced a brief period of Persian rule at the turn of the 5th century BCE, but the Greeks recaptured it during the Greco-Persian Wars. Byzantium then continued as part of the Athenian League and its successor, the Second Athenian League, before gaining independence in 355 BCE. Long allied with the Romans, Byzantium officially became a part of the Roman Empire in 73 CE. Byzantium's decision to side with the Roman usurper Pescennius Niger against Emperor Septimius Severus cost it dearly; by the time it surrendered at the end of 195 CE, two years of siege had left the city devastated. Five years later, Severus began to rebuild Byzantium, and the city regained—and, by some accounts, surpassed—its previous prosperity.
Istanbul