[My answer being very long, I posted it on my blog with pictures to make it more enjoyable to read. Make sure to check it ;-) https://asinusdocet.wordpress.com/2019/04/09/fantastical-monsters-and-animals/]

[part 1]

The literature of bestiaries evolved substantially from the 5th to the 15th century. The founding stone of this literature is nonetheless the Physiologus, written in Greek in the 2nd century and translated into Latin in the 4th or 5th century. This work consisted in 48 description of animals, real or imaginary, such as the lion or the unicorn, mostly based on fables and literary tales. The success of this book cannot be underestimated. It was only rivalled by the Bible. It also counted amongst the first work translated into vernacular language around the 11th century.

Though the Physiologus was read generation after generation as surely as the Bible or saint Augustine’s works, and even though the Physiologus was translated and adapted to many literary format (an unknown “Thetbaldus” made a metrical Latin version of 13 of its sections), scholars slowly added on it and developed a literature of bestiaries that became a genre in itself. It all began, of course, with Isidore of Seville (c. 556-636) and his renowned Etymologiae, and etymological encylopedia that was a sum of knowledge every scholar deserving the name would study and learn by heart in the next centuries. The Etymologiae had a very specific goal: explain the nature of every single thing known to mankind by looking at the origin of the words used to designate them. This tend to offer somewhat funny statements: “The Tigris is so called because the fowl of panic and flight, for this is what they call the Persians and the Medes at an arrow. It is a beast with various markings, and the speed of the power of wonderful by whose name the river is called the Tigris, and it is the most rapid of all rivers.” (Isid. Etym. 12:2,7) [link to source] Isidore describes indeed the tiger as one of the fastest animal there is and justify this assertion by stating that its name derives from the Tigris river (located in the Middle East), which is “the most rapid of all rivers”. But more on the tiger in a moment…

When writing on animals, Isidore used the Physiologus but multiplied his sources, quoting Pliny and many others. Scholars writing after Isidore would only reinforce that method. By the 13th century, Thomas Cantipratensis wrote a sum of his own, the De Natura Rerum, which renders Isidore’s work totally obsolete. Thomas names his sources systematically and adds many to those used by Isidore. Meanwhile, he also pushes the symbolic interpretation of animals much farther.

A common trait of medieval scholarship was to assume that our world was only the reflection of a higher reality: God’s own realm. This idea was summed up in the concept of “speculum” or “mirror”. Therefore intellectuals had the difficult task to uncover the hidden meaning of everything around us, through some sophisticated symbolic reasoning that was guided by faith and the word of God.

More on the tiger now. And I will basically sum up Clara Wille’s article “Le Tigre dans la tradition latine du Moyen Âge”, adding here and there some information of my own. This will help us understand how the literature of bestiaries evolved from the 5th to the 15th century.

The tiger was a well-known animal in India and it is notable that the Physiologus has a distinct Indian influence. The animal was introduced to the Roman world in the first century when Augustus received some tigers as a gift from an Indian embassy. It quickly became a famous pattern for mosaics and we often find it depicted as Bacchus’ personal steed.

Tigers totally disappeared from Europe after the fall of the Roman Empire. We have to wait 1475 for Greeks to showcase tigers in Italy. Therefore we shouldn’t be surprised if medieval scholars totally misrepresented the tiger in their works. By the 12-14th century, the tiger is either depicted as a kind of dog, big cat or some fantastic creature, but looks nothing like the actual animal we know (and love).

I’ll let you be the judge of it. In the famous Aberdeen bestiary, the tiger is a blue creature with white and red spots. However what I uncovered myself were the very diverse depictions of the tiger in manuscripts that all derived from a single same source: Petrus Berchorius’ De formis figurisque deorum, written in the 14th century. This introductory chapter of the Ovidius Moralizatus indeed describes Bacchus and sits him on a tiger. Plus, the De formis figurisque deorum quickly became a manual in itself for every artist that wanted to depict the pagan gods of old. Therefore, many manuscripts somewhat related to Berchorius’ work and depicting the pagan gods display the picture of a “tiger”, Bacchus riding it. You’d expect all those tigers to look alike since they are all derived from the same written source. Think twice.

The tiger looks like an exotic our monstrous horse in this wonderful Vatican manuscript (go to folio 5v), in Conty’s Echecs Amoureux moralisés and in the Bible des Poëtes. It is obviously a wolf in the Chronique de Hainaut (sorry, I got no link for this one). But more surprisingly it is either a monstrous dog or cat, a hippogriff, or a regular horse in the various manuscripts of Ovide moralise (links: Citta del Vaticano, BAV, MS Reg. lat 1480, go to the folio 176r; Geneva, BM, MS fr. 176, f. 177r; Paris, BnF, fr. 137, f. 182v).

However, by then, the zoological aspect of the tiger had less importance for medieval scholars than the symbolic interpretation of its assumed characteristics. In the very same manner, legendary creatures were studied very seriously even if their physical aspect were deemed of little or no importance. The phoenix was certainly very popular, but mostly because of its Christological interpretation. To my knowledge, no one ever claimed to have seen or hunted one.