This research focuses on study the historical bronze window grilles of Sabil al-Ahmadi in Tantacity, in the Egyptian Delta region, which comprises three windows made of bronze. Acomprehensive analysis was carried out for one of these windows using digital and metallographic microscopes, portable X-ray fluorescence (pXRF), scanning electron microscopy with energydispersive spectroscopy (SEM/EDS), and X-ray diffraction (XRD). These techniques were used to determine the composition of the alloy, its metallurgical properties, and the nature of its corrosion. The window grille was identified as being made of a quaternary bronze alloy (Cu, Zn, Sn, Pb), produced through a sand-casting process. The corrosion layers consisted primarily of cuprite and clinoatacamite, with dense layers of dust containing calcite, quartz, and gypsum. A series of mechanical cleaning processes were employed to remove tough incrustations and corrosion products, followed by the application of a protective coating, PUR-129,which has proven its effectiveness in experimental studies conducted to assess its efficiency. This coating was selected for its durability, strong adhesion, and ease of application, ensuring the long-term preservation of the bronze window.