Short answers, pulled from the story.
Herodotus states that the traditional founding of Byzantium occurred in 667 BCE. This date marks when Byzas, a king from Megara, sailed northeast across the Aegean Sea to establish the settlement.
One theory suggests Thracian roots derived from the personal name Byzas meaning he-goat. Pliny the Elder mentions an earlier name Lygos corresponding to a Thracian settlement before ancient Greek texts used Byzántios for inhabitants.
Constantine I refounded the city as Nova Roma in 330 CE inspired directly by Rome. Later generations called it Constantinople meaning city of Constantine in Greek after making it the capital of what historians now call the Byzantine Empire.
A bright light appeared in the sky during a dark wet night in 340 BC when Philip of Macedon attempted a surprise attack against Byzantines and their Athenian allies. The Byzantines erected a statue of Hecate lampadephoros to commemorate this event which thwarted his forces.
Ottoman Turks conquered the city on the 29th of May 1453 and named it Istanbul though official renaming did not occur until 1930. Ankara remains the national capital today while Istanbul stays the largest population center.