During the Roman Empire, a new type of ink called iron gall ink was developed, made from tannin (from oak galls) and iron salts. This ink was more permanent and water-resistant than carbon-based inks, and it became the standard writing fluid in Europe for over a thousand years. It was used extensively for manuscripts and official documents.

Iron gall ink was the ink used by medieval scribes to copy classical and religious texts, including the poetry of Virgil, Ovid, and Horace. Its permanence ensured the survival of these works through the Middle Ages. However, its corrosive properties have also damaged many manuscripts, a challenge that modern conservators still face.