In front of the Golden Gate there was this other gate, that you will later see from the outside. See below:

The gates were covered with gold plate, hence the name, and the facade was covered with sculptures, the most famous of which was a bronze group of four elephants. The gate was incorporated within the land-walls when Theodosius II decided to extend the city. Strolling through Istanbul (Redhouse) claims: "It was presumably in connection with this new wall that he built the small marble gate outside the triumphal arch; the arch itself, of course, could have no gates, except for ornamental iron or bronze grills, and would have been indefensible. The outer gateway is part of the general system and forms, with the curtain walls which join it to the city walls near the polygonal towards, a small courtyard in front of the Golden Gate.