The site carries layers of naming that stretch back well before the Byzantine period. In Greek antiquity, the promontory was sacred to Hera, queen of the Olympian gods, and it was called Heraion akron — the Cape of Hera — in reference to that dedication. Over centuries the name compressed and shifted, becoming Hieria in Byzantine Greek, with variant spellings including Hiereia, Hieria, and Heria. The place also appears in ancient sources under the names Heraeum and Heraion. Modern Istanbul has replaced all of these with Fenerbahçe, a Turkish name meaning 'lighthouse garden,' which now belongs to a neighborhood on the Asian side of the city, well known today as the home of one of Turkey's most famous football clubs.

The Emperor Justinian I, who reigned from 527 to 565, was one of the great builders of the late antique world. His reign produced Hagia Sophia, the most ambitious church ever built up to that time, and dozens of other monuments across the empire. At Hieria, on this promontory above the Bosphorus, he built an imperial palace that served as a retreat outside the walls of Constantinople proper. The complex included a harbour — the Bosphorus made such a facility natural — and a church dedicated to St. Mary. The precise extent and appearance of the palace are not well documented, and little physical trace survives above ground, but its existence is confirmed by historical sources and it appears to have remained in imperial use through the Byzantine period.

Hieria's most consequential moment in Byzantine history came not from its palace but from a church council held there in 754, during the reign of Emperor Constantine V. The Council of Hieria was convened to settle — or rather, to enforce — the emperor's iconoclast position: the destruction of religious images throughout the empire. The council issued a decree condemning the veneration of icons, a ruling that touched off decades of conflict between iconoclasts and iconodules (those who defended the use of images in worship). The Second Council of Nicaea in 787 reversed the Council of Hieria's decisions, but the controversy it embodied reshaped the relationship between imperial authority and church doctrine for generations.

Standing at Fenerbahçe today, with ferries crossing the Bosphorus and the towers of European Istanbul visible across the water, it takes some imagination to reconstruct the Byzantine landscape. But the geography hasn't changed: the promontory still juts into the strait, the view of the European shore is still unobstructed, and the sense of being at a threshold — between continents, between seas, between worlds — remains. Hieria was not one of Constantinople's famous monuments. It was a place apart, deliberately so, built at a remove from the city's noise. That quality of apartness is still detectable in Fenerbahçe, a neighborhood that sits just to the side of central Kadıköy and has always seemed slightly its own.