Elephants
The Grand Medieval Bestiary: Animals in Illuminated Manuscripts

Many of the medieval European illustrators who created illustrations of elephants -- either as decorative elements or as illustrations in breviaries -- did so without ever having seen one in person. Perhaps to some of these illustrators, the idea of an elephant was just as "real" as a unicorn or a dragon, and so the elephant was drawn either from reading a description or copied from yet another illustrator.

Elephants were, of course, the primary source of the ivory that was used to create many decorative items, especially in the later Middle Ages, such as mirrors, combs, handles for knives and forks, paternoster beads, chess pieces, writing tablets, and boxes. Oliphants were also carved from elephant ivory.

See also Avorio d'ogni ragione: the supply of elephant ivory to northern Europe in the Gothic era in Journal of Medieval History, vol. 36, no. 2, as well as The Medieval Bestiary: Elephant and The Elephant in Medieval Legend and Art.