While they weren't always depicted as shirtless teen heartthrobs, creatures who turn from human into wolf (and vice versa) appear in tales dating back to antiquity. So throughout the Middle Ages and the Renaissance, artists have had plenty of strange and creepy stories to inform their werewolf illustrations.

A priest administering last rites to the dying wife on the right while the cursed husband is standing on the left, a miniature from Topographica Hibernica, c. 1196-1223

(via British Library)

Dog-headed men from Livre des merveilles du monde, a 13th-century travelogue with stories told by Marco Polo

(via Wikimedia Commons)

An illustration from a book that tells a cycle of romances about Alexander the Great, illustrated by Jehan de Grise in the late 14th century

(via Oxford University)

Werewolf, by Lucas Cranach the Elder, c. 1512

(via Wikimedia Commons)

Witch turned werewolf attacking travelers, a woodcut by Hans Weiditz, from Die Emeis, written by Dr. Johann von Kaysersberg, 1517

(via Symbolforschung)

A 16th century copperplate engraving of Lycaon, the king of Arcadia, transformed into a wolf by Zeus, made by Italian artist Agostino de' Musi

(via Karl Shuker)

King Lycaon, on an engraving from Ovid's Metamorphoses Book I, made by Hendrik Goltzius, 1589

(via Wikimedia Commons)

The werewolf of Eschenbach, Germany, trapped in a well, 1685

(via Many Interesting Facts)

Another engraving of the Werewolf of Eschenbach, 1685

(via Pinterest)

The Beast of Gévaudan, "a calf-sized men-eating wolf" that attacked about 210 people, resulting in 113 deaths (98 of them were partly eaten), between 1764 and 1767

(via Frank Zumbach, Maria Antonia)

Two wolves eating a sheep, from the cover of Wie man die falschen Propheten erkennen (How to recognize false prophets), 1809

(via Google Books)