 Despite these observations, they never really truly understood the risks of the mineral. Asbestos continued to be used throughout the world throughout the Middle Ages, though it seems to have declined somewhat. Charlemagne, first emperor of the Holy Roman Empire, was said to have had an asbestos tablecloth that he impressed dinner gifts with by tossing it into the fire at the end of the meal. In the early modern period, scientists turned to the utility of asbestos. Research into the material exploded starting in the 17th century.