Along the Land Walls - Strolling Through Istanbul: The Classic Guide to the City - page 351

hence the name - and the façade was decorated with sculptures, the
most famous of which was a bronze group of four elephants, placed
there to commemorate the triumphal entry of Theodosius after his
victory over Maxentius. When Theodosius II decided to extend the
city two decades later, he incorporated the Golden Gate within his
new land-walls. 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 had no gates, except for ornamental
iron or bronze grilles, and would have been indefensible. The outer
gateway is part of the general system of defence and forms, with the
curtain wall which joins it to the city walls near the polygonal towers,
a small courtyard in front of the Golden Gate.
After the time of Theodosius I, the Golden Gate was several times
the scene of triumphal entries by victorious emperors: Heraclius
in 629 after his defeat of the Persians; Constantine V, Basil I, and
Basil II after their victories over the Bulgars; John I Tzimisces after
his defeat of the Russians; Theophilus and his son Michael III after
their victories over the Saracens. Perhaps the most emotional of all
the triumphal entries was the one that occurred on 15 August 1261,
when Michael VIII Palaeologus rode through the Golden Gate on a
white charger after Constantinople was recaptured from the Latins.
But that was the last time an Emperor of Byzantium was to ride in
triumph through the Golden Gate, for the history of the Empire in
its last two centuries was one of continuing defeat, and by then the
gateway had been walled up for good.
YEDİKULE TO BELGRAD KAPISI
From Yedikule to the next gate, Belgrad Kapısı, it is possible to
walk either on top of the great wall or on the terrace below, for the
walls here are in quite good condition. All of the 11 towers which
guard the inner wall in this stretch are in quite good condition, as
are all but one of those in the outer wall. An inscription on the
eighth tower in the inner wall records repairs by Leo III and his son
Constantine V in the period 720-41, and one on the tenth tower
of the outer wall notes that it was restored by John VIII Palaeologus
in 1434.