A MULTI-ANALYTICAL APPROACH TO THE STUDY OF THE MURAL PAINTINGS IN THE PRESBYTERY OF SANTA MARIA ANTIQUA AL FORO ROMANO IN ROME* S. R. AMATO, 1 †‡ D. BERSANI, 1 P. P. LOTTICI, 1 P. POGLIANI 2 and C. PELOSI 3 1 Department of Physics and Earth Sciences, University of Parma, Parco Area delle Scienze 7/A, 43124, Parma, Italy 2 Department for Innovation in Biological, Agro-food and Forest Systems, University of Tuscia, Largo dell’Università, 01100, Viterbo, Italy 3 Department of Economics and Management, University of Tuscia, Largo dell’Università, 01100, Viterbo, Italy This paper presents the results of analyses carried out on three decorative phases of the pres- bytery of the church of Santa Maria Antiqua al Foro Romano in Rome: the fourth-century AD mosaics setting bed; the Adoration of the Cross, dated to the papacy of John VII (AD 705–7); and the paintings in the apse of the Pope Paul I (AD 757–68) phase. The research allowed the characterization of the painting techniques, pigments, organic compounds and degradation products by means of a video microscope, optical microscopy, and μ-Raman and FT–IR spectroscopy, contributing to a better understanding of the changes in the techniques and materials used throughout the centuries in one of the most relevant medieval Christian monuments in Western Europe. KEYWORDS: ROMAN FORUM, MIDDLE AGES, WALL PAINTINGS, IN SITU INVESTIGATION, μ-RAMAN SPECTROSCOPY, FOURIER TRANSFORM INFRARED SPECTROSCOPY INTRODUCTION The church of Santa Maria Antiqua, located inside the Foro Romano in Rome and adapted from an Imperial Roman building, is a monument of the utmost importance for understanding the development of early medieval and Byzantine art in Rome. The paintings hosted in this church represent the chronological sequence of a series of decorations painted at various times from the Imperial age until the ninth century AD. They are precious evidence of the stylistic, iconographic and technical choices made by patrons and masters in Rome between Late Antiquity and the Middle Ages. This research is the outcome of a collaboration between the Università degli Studi di Parma and the Università degli Studi della Tuscia as part of the research project Santa Maria Antiqua, organized by the Università degli Studi della Tuscia and directed by Maria Andaloro from 2000, with the aim of studying the decorative phases of this monument from both an art-historical and a technical point of view. Thanks to the complete restoration of the paintings in the church’s presbytery (Fig. 1 (a)) in 2011 and 2012, a diagnostic survey campaign was carried out, focusing on the characterization of the materials of three specific phases: (1) the fourth-century AD remains of bedding mortars *Received 5 April 2016; accepted 25 November 2016 †Corresponding author: email silviarita.amato@studenti.unipr.it ‡Current address: Department of Conservation and Technology, The Courtauld Institute of Art, Strand, London, WC2R 0RN, UK. Archaeometry ••, •• (2017) ••–•• doi: 10.1111/arcm.12296 © 2017 University of Oxford