The only surviving fresco wall-paintings by Panselinos (13th c. ad), one of the most celebrated Greek religious painters of the Byzantine era, decorate the Church of Protaton (10th c. ad) on Mount Athos. This article details the examination and technical analysis of 15 thematic units, representative of this monumental work of art. The wall-paintings examined cover an area of approximately sixty-five square meters. Extensive study and documentation of both original paintings and already restored frescoes were attained through the use of various imaging techniques, including visible and ultraviolet photography, infrared reflectography (IRR), and colour measurement and representation. Chemical identification of pigments, binders and layer stratigraphy was achieved by using visible and ultraviolet fluorescence microscopy. Raman spectroscopy, Fourier Transform Infrared spectroscopy (FTIR). X-Ray Diffraction (XRD). Scanning Electron Microscopy with Energy Dispersive Analysis fSEM-EDS), and Electron Probe Microanalysis (EPMA). The results of this collaborative effort have shown the paintings to be executed in both the true fresco and the lime painting technique, and have established Panselinos’ choice of painting materials and colour palette. This study is an important and necessary prerequisite for the eventual restoration and conservation of these unique wall-paintings.