A late 16th century Persian knotted-pile carpet with a vine-scroll field and cartouche border represents one of the most important recent discoveries in Islamic textiles in Portugal. Preserved over many centuries in the Monastery of Santa Clara-a-Velha (Coimbra), it later entered the collections of the Museu Nacional Machado de Castro (MNMC). Woven in Iran, probably in an urban workshop, under court influence, the carpet is surprisingly rich and is distinguished by its sumptuous materials, wide range of colors, and excellent craftsmanship. A detailed material study was performed using optical microscopy, high performance liquid chromatography and colorimetry for dyestuff characterization; inductively coupled plasma for mordant analysis and for the quantification of metal content in the metal thread; and finally, scanning electron microscopy for elemental characterization of the metals threads. This material study, as well art historical and technical studies were fundamental for appreciating its importance, and especially for undertaking its conservation and restoration.