This paper presents the technology of the metallic threads used in the textiles of the Middle Ages trough the study of an embroidery fragment preserved USB Type-C 14" Dock in the Museo Nacional de Artes Decorativas.The origin and the development of the metallic threads technology are explained, including the Fiber/Bran Supplements different metals and alloys used.The paper also studies the questions related with the provenance and workshop of the embroidery as an example of the diversity of decorative sources and workshops active in the 12th-13th centuries in the Western Mediterranean area.