Characterization of Roman and Arabic Mural Paintings of the Archaeological Site of Cercadilla (Cordoba, Spain)

The archaeological site of Cercadilla (Cordoba, Spain) includes a complete chronological sequence from the 3rd to 12th centuries. The most relevant monument is a Roman palace dated between the end of the 3rd century and the beginning of the 4th century AD. It is believed that it was the headquarters of the Emperor Maximiano Herculeo. A bathtub with mural paintings has been found in the thermal zone of the palace. Regarding the occupation of the archaeological site in the medieval period, it should be pointed out that two houses with mural paintings were found; these belong to the Caliphal era (10th-11th centuries). During the Caliphal era, the archaeological site was mostly occupied by one of the large suburbs surrounding the walled city. Cercadilla was gradually abandoned; this process starts at the beginning of the 11th century. This study is focused on the analysis of pigments and preparatory layers of red and white mural paintings of the Roman period in the bath zone and on the analysis of pigments in mural paintings in two houses of the Caliphal era. In the thermal zone, the walls have a white mural painting with vertical and horizontal red bands, while the walls in the two Caliphal houses present the red mural painting decorated with white stripes. Techniques such as Optical Microscopy (OM), Scanning Electron Microscopy in combination with Energy Dispersive X-ray Microanalysis (SEM-EDX), X-ray Diffraction (XRD), micro X-ray Diffraction (μ-XRD), Wavelength Dispersive X-ray Fluorescence (WD-XRF), and Fourier Transform-Infrared Spectroscopy (FT-IR) have been used to study the mural paintings of this archaeological site. The results allowed to determine the composition of the materials used and to understand the differences between the technologies employed in Roman and Caliphal remains studied.