In the Vinica Fortress, Republic of Macedonia, 50 undamaged terra cotta icons and 100 fragments, all dated 6th-7th century, were found. In order to determine the provenance of these unique terra cotta icons, the mass fractions of 19 different chemical elements were previously determined in ten fragments of the terra cotta icons and thirty three samples of clays from eight different sites from the region. Due to the dimensionality and complexity of the experimental data, the archaeometric results were treated with self-organising maps (SOM). The results obtained using SOM were compared with the ones obtained using principal component analysis. Both chemometric methods revealed that Vinica terra cotta icons were made from clay from Grncarka, 2.5 km South-East from the Vinica Fortress.