At the Natural History Museum in St. Gallen, Switzerland is a taxidermied crocodile from 1623. It is the museum's oldest exhibit and thought to be the oldest example of taxidermy still in existence.  The museum had initially been established as library in the former monastery of St. Katharine in 1615. Brought to Switzerland from Egypt by Ulrich Kromm, the stuffed crocodile was sold to Daniel Studer, who then bequeathed the creature to the city's library in 1623.  It was in great part due to the arrival of such a natural wonder, as Georg Caspar Scherer explains in his history of the library, that prompted the directors of to collect not only books but also, when the opportunity arose, rarities from the natural world. In 1644 the following "Merkwurdigkeiten" or marvelous curiosities were purchased for 24 Reichsthaler: the skeleton of a human and a dog, the backbone of a whale, and the mould of a swordfish. And so the collection began to grow. 

Now more than 350 years old, the crocodile was restored to its former glory in 1994 and is still the museum's most prized specimen.  

Image: taken from Geschichte des Naturmuseums St. Gallen, kindly sent to me by Dr. Toni Burgen, director of the Museum.

Other early examples of preserved crocodiles include one given to King Alfonso X by the Sultan of Egypt in 1260. When the animal died, its body was dried and hung in the Portal of the Lizard (named for the reptile) which leads from the cloister to the Cathedral of Seville. The crocodile eventually decayed, however, and was replaced by a wooden replica.

Although medieval churches frequently hung preserved exotic items to evoke awe at the wonderous variety of God's creations, the crocodile has a more precise significance for early Christians. The crocodile is the symbol of St. Theodore, martyred in 306. As the story goes, St. Theodore was a soldier in the Roman Empire when an edict was issued against the Christians.  He was ordered before the magistrates and was asked to offer a sacrifice to the gods.  When he refused, proclaming his belief in the divinity of Jesus Christ, the magistrates gave him some time to consider as he was still a very young man.  Rather than ponder, he acted and burnt down the Temple of Cybele, a crime for which he was burnt at the stake. The crocodile represents one of the Roman gods he destroyed.  St. Theodore was adopted as patron saints of Venice and can be seen represented atop one of the two Byzantine columns standing in the Piazzetta of the Piazza San Marco, treading upon the sacred crocodile of Egypt.

Crocodiles (undistinguished from aligators) were almost indispensible items in cabinets of curiosity - and the bigger, the more provocative and curious. As Borrilly had four crocodiles; Trichet had one five feet long, and Borel's crocodile (classified with the quadrupeds) was not less that nine feet. Bernon possessed two crocodiles from Egypt, two from America, one cayman, and two crocodile eggs. Ferrante Imperato had an enormous crocodile hanging from the ceiling of his collection.  Sir Hans Sloane tried to bring a small crocodile back to England from the South Indies in a tub of salt water. He kept it alive for several months on food scraps, but it eventually died although in a much less spectacular fashion than Sloane's iguana (which was frightened by a sailor, leapt overboard, and drowned) and an enormous yellow snake (which escaped from its barrel and was shot).