As part of the research undertaken on easel and mural paintings by or attributed to Thomás Luis (c.1565-c.1612), an interdisciplinary diagnostic is presented in this paper regarding tow sixteenth-century fresco-ceilings at Palácio dos Condes de Basto, actual Fundação Eugénio de Almeida (FEA), attributed to this artists by Vítor Serrão [3, 4]: “Tomada de La Goleta” and “Armas”. Aiming their safeguard pathologies...