The element titanium has been identified in a number of inks from historical documents. However, no further analyses of these inks have been carried out in order to determine in what molecular form the titanium is present. This paper emphasizes the need for further studies of historical inks and provides information about their preparation, which suggests that the compound anatase might be present as a component of medieval inks. The reported presence of anatase in the Vinland Map ink has previously been forwarded as evidence of the modern manufacture of the map. Other elements, such as copper, zinc, and aluminum, that are present in the Vinland map ink, are shown to be consistent with the medieval method of preparation of green vitriol, a known component of inks, which strongly suggests that the Map's ink is medieval.