The Golden Horn was a natural port, particularly the Eminönü/Sirkeci shore, which being on a peninsula was also eminently defensible. It was this location that led to the foundation of Byzantium, and from here that the city grew, with the oldest neighbourhoods being the port districts along the Golden Horn. In the 12th century, the Byzantine port was also occupied by merchants from Venice, Amalfi, Genoa and Pisa, who eventually acquired their own wharfs and waterfront districts.
In the Byzantine period, the modern area of Eminönü included the districts of Neórion (after the war harbor located there), Akrópolis, Kynégion, Arcadianae/Arkadianaí, ta Hormísdou, Amantíou, Caenopolis/Kainópolis ("New City"), ta Kanikleíou, ta Narsoú, ta Kaisaríou, Artopoleía (the "bakeries"), Argyroprateía (the "silver vendors"), Chalkoprateía (the "bronze vendors"), ta Olybríou, Constantinianae/Konstantinianaí, ta Amastrianón, Eugeníou, Pérama ("Crossing", the place where the ferry to Galata sailed), Zeúgma, Stauríon, Vlánga, Heptáskalon.
The Golden Horn was still a thriving port in Ottoman times, occupied by importers, warehousemen, sailors and traders of every description, the centre of trade in the city, a labyrinth of narrow streets, workshops and markets leading uphill to Topkapı Palace, the Ottoman capital.
The name of the neighbourhood, Eminönü, reflects its place in history. Translated from Turkish to English it roughly means 'in front of justice'. Emin meaning 'justice', önü meaning 'in front of'. The name most probably came from the Ottoman courts and customs houses on the docks; "Emin" was the title of an Ottoman customs official.
The nature of the place was changed by the industrial age; the Galata Bridge was built across the Golden Horn; steamships arrived, then electricity, then the railway and the Istanbul terminal of the Orient Express was naturally sited at Sirkeci Station. The sea walls still surrounded the city, and the sea gates of the port of Eminönü were the point of entry for goods, and for people. Eminönü was a part of the Fatih district until 1928. She became district of İstanbul in 1928.
In the wake of the huge railway station, other grand stone buildings were also built in the late Ottoman period. Among these were the Main Post Office and some commercial buildings like Istanbul 4th Vakıf Han. In the early days of the Republic of Turkey, Eminönü was renovated extensively; the big square was opened up in front of Yeni Cami by clearing out the tollbooths at the end of the Galata Bridge; the Spice bazaar was restored; the fish market was cleared off the shore of the Golden Horn and a road opened up to the new bridge at Unkapanı.
By the 1950s, the area was continuously clogged up with traffic, which was eased somewhat by the construction of the large coastal road around the point and all the way out to Istanbul airport.(Wikipedia)