A selection of historical textile fragments from the Venetian art dealer Moisè Michelangelo Guggenheim collection, ranging from XV to XVIII century, has been investigated by means of non-invasive techniques in order to reveal the coloring materials. Imaging was preliminarily used to visually investigate the selected artwork fragments in order to investigate their structure and conservation conditions; Fiber Optics Reflectance Spectroscopy (FORS) allowed recognizing the main natural dyestuffs, such as indigotin and anthraquinones-based compounds, except the yellow ones, difficultly identifiable when using this non-invasive technique. Collected spectroscopic data have been also elaborated by using a clustering algorithm that permitted to group collected spectra on the basis of similar properties and evidencing their inflection point wavelength as the most influencing feature. Display omitted •The antique dealer M. M. Guggenheim assembled a wide textile collection.•A selection of fabric fragments ranging from XV to XVIII century was studied.•FORS analysis allowed identifying dyestuffs such as indigotin and anthraquinones.•Flavonoids were found in yellow areas but no further classification was possible.•Clustering analysis allowed grouping FORS spectra according to their spectral similarities.