This paper engages with the changing Ottoman attitude towards pre-Ottoman edifices by focusing on the use, reuse, appropriation, documentation, and museumification of Byzantine remains in and around Topkapı Palace. Ottoman relationship with the Byzantine pasts of Istanbul had been ambiguous and went through different phases from the 15th to the 20th century. The palatial complex was built over the Byzantine acropolis by Mehmed II and numerous Byzantine remains scattered around the palace were spoliated and reused for decorative or merely functional purposes. Yet, with the increasing awareness of the past during the early modern and modern eras these “antiquities” started being documented, displayed, and museumified. For instance, the Byzantine church of St. Irene, remaining in the first courtyard of Topkapı Palace, was not converted into a mosque, but used as an armory after the conquest until its conversion into a proto-museum of antiquities in the mid-19th century. Numerous other objects in the palace that were previously spoliated or functionally utilized, were transformed into antiquities to be observed, displayed, and documented. One such case was the baptistery, which was used as a storage for gold and silver coins in the basement of the Ottoman Imperial Treasury for many centuries. The marble basin was later removed and placed in the fourth garden of the palatial complex. Documentation of Byzantine heritage also became important. For instance, Byzantine sarcophagi found in the second court of the palace were documented as early as the 18th century and another later discovery was marked by inscriptions carved on marble columns of the portico. These imperial tombs were eventually unearthed and transferred to the Ottoman Imperial Museum, which was established in the palace grounds during the late 19th century. By the early 20th century, accidental discovery of Byzantine architectural remains during the making of the Gulhane Park, became a public incident to be advertised and celebrated by the mayor of Istanbul. Drawing upon first-hand on-site documentation, as well as unpublished archival material, architectural surveys, archeological reports, official correspondences, photographs, engravings and memoirs, the study will present the ambiguous engagement of Ottomans with the Byzantine past in and around the Topkapı Palace. This study focusing particularly on Topkapı Palace will shed light on the larger phenomenon of Ottomans’ perception of and engagement with the Byzantine heritage and discuss their changing responses towards the pre-Ottoman pasts of the empire from the foundational era to the dissolution of the empire.