Exceptional Byzantine Lead Seal of the Oikonomion (Treasury) of Hagia Sophia – Constantinople Early 12th Century AD A remarkably rare and historically significant Byzantine lead seal from the Oikonomion (Treasury Administration) of Hagia Sophia in Constantinople. Material: Lead Diameter: 56 mm Weight: 128.51 g Obverse: The Virgin Mary (Theotokos), seated on a throne and holding the Christ Child, who raises His right hand in blessing. On either side stand five crowned Byzantine emperors, dressed in the imperial loros, each presenting a scroll representing imperial donations to Hagia Sophia. The surrounding Greek inscription identifies the Treasury of Hagia Sophia. Reverse: A six-line metrical Greek inscription referring to the administration of the Treasury of Hagia Sophia and invoking divine protection over the treasury and the subjects of the Byzantine Empire. Rarity: This seal belongs to an extremely small group of known examples published in major scholarly references, including Geneva 275, Wassiliou-Seibt (No. 932), Zacos Spink II, and Zacos & Veglery I. The present specimen is considered only the second known example and is regarded as the best-preserved specimen recorded. Historical Importance: Besides its exceptional rarity, this seal is of great linguistic importance because it preserves Greek accent and breathing marks, a feature almost never found on Byzantine lead seals. These orthographic signs, normally reserved for manuscripts, make this seal an outstanding object for both Byzantine historians and collectors. Condition: Well struck, well centered, with an attractive original patina. Minor signs of age and handling; otherwise in Very Fine condition. An exceptional museum-quality Byzantine seal of great rarity, historical importance, and outstanding collector appeal. Acquired in 2025 from Demeter Coins Falk Zünkler in Germany. Provenance: The piece was formerly part of a private collection in Spain, having been acquired in 1987 from an antiquities dealer or gallery. This rare piece is accompanied by the original purchase invoice and a certificate of authenticity.