Pera, which later developed into Istanbul, was an area surrounded by the city walls built partially by Emperor Theodosius II. This area, encompassing the slopes overlooking the Golden Horn and the Sea of Marmara, consisted of residences. Around Sirkeci, there were commercial establishments, while important administrative, religious, and commercial centers were concentrated in locations like Sarayburnu, Beyazıt, Aksaray, Cerrahpaşa, and Yedikule. Additionally, across the Golden Horn, Galata also became an outer settlement. The majority of the inhabitants of the settlement called Sykai (Sycae) were Venetians and Genoese. Later, as these areas became enclosed by city walls, they became prosperous trade centers.

This passage provides historical insights into the development of different parts of Istanbul during the Byzantine era, with a focus on the growth of Pera, Sykai, and Galata as important centers of commerce and culture.