The collection of Byzantine seals of the State Hermitage Museum includes over 12.5 thousand pieces. For the purpose of the paper the author distinguished seals, which legend indicates a toponym related to the capital of the Byzantine Empire, Constantinople. As a result, 122 seals, the majority of which were never made public before, were selected. Most of them date back to the 6–12th centuries and include the seals of Patriarchs of Constantinople, Hagia Sophia (Church of the Holy Wisdom), churches and monasteries of Constantinople: monasteries of Panagia Acheiropoietos, Panagia Peribleptos, Chalcoprateiois, Didim, Kosmidion, Lips Monastery, Myrelaion, the New Church, Monastery of Christ Philanthropos and others, as well as diaconica (St. Athansius, Dexiokratous, Eusebius), St. Zotikos Brotherhood, St. Sampson Hospital. However, the majority of the selected seals belong to civil servants: eparchs of the city, commerciarioi, curator of the Pigi Palace and Eleutheria. The discoveries made significantly added to the scientific understanding of historical and, above all, ecclesial geography of Constantinople between the 6th and the 11th centuries, as well as listed the names of the civil and ecclesial servants. The paper discovered several specifics of church-state relations in the
 Byzantine Empire, exemplified by the churches of the capital city. The findings made allow to trace the historical changes in seals of Constantinople patriarchs.