Around 1480 when he was not yet thirty, Leonardo da Vinci wrote about what may have been a seminal event in his life. In writing of his travels to view nature he recounted an experience in a cave in the Tuscan countryside:
Having wandered for some distance among overhanging rocks, I came to the entrance of a great cavern…[and after some hesitation I entered] drawn by a desire to see whether there might be any marvelous thing within…(Leonardo da Vinci, Codex Arundel, fol. 155r).
On the next folio he continued, describing what appears to have been a fossil whale embedded in the walls of the cave:
O powerful and once-living instrument of formative nature, your great strength of no avail, you must abandon your tranquil life to obey the law which God and time gave to creative nature. Of no avail are your branching, sturdy dorsal fins with which you pursue your prey, plowing your way, tempestuously tearing open the briny waves with your breast.
Oh, how many a time the terrified shoals of dolphins and big tuna fish were seen to flee before your insensate fury, as you lashed with swift, branching fins and forked tail, creating in the sea mist and sudden tempest that buffeted and submerged ships…
O Time, swift despoiler of created things, how many kings, how many peoples have you undone? How many changes of state and circumstances have followed since the wondrous form of this fish died here in this winding and cavernous recess? Now unmade by time you lie patiently in this closed place with bones stripped and bare, serving as an armature for the mountain placed over you (Leonardo da Vinci, Codex Arundel, fol. 156r).
Leonardo's interest in fossils and his prescient grasp of what is now known as geomorphology are well documented. However, the influence on Leonardo of this early encounter with a "wondrous form" has not been fully examined, and there is skepticism among some scholars as to whether it actually took place. The passage often has been interpreted as a poetic reference to Ovid or Seneca, both of whom wrote of caves, the metamorphosis of the earth, and in the case of Seneca, even subterranean fishes. But I propose instead that Leonardo did enter one of the many caves that punctuate the Tuscan landscape, and there saw something marvelous that would stay with him for the rest of his life.
Prehistoric whale bones have been found across Italy, including Tuscany. A large bone is still displayed on a house in La Lisca, a locality less than 20 miles west of Florence (fig. 1), and fossilized bones of a behemoth recently were unearthed in the Tuscan region of Orciano Pisano (fig. 2). It is entirely possible that Leonardo's description of the ancient creature was based on a personal experience; further evidence that the above entry described fossilized remains may be found in a nearby passage in the Codex Arundel (fol. 156v) in which Leonardo refers to "two lines" (very likely fossil layers) of shells in the earth. He postulated that the first layer was made when it was submerged by the sea, and the second layer was made by the Deluge or Flood. In this early writing (also datable between 1475 and 1480) he followed common knowledge and partially attributed the layering of fossils to the Flood, but in later writings he soundly rejected this idea. Leonardo wrote extensively about what is now known as geomorphology and paleontology in the Codex Leicester, and in fol.1v he described changes in the extent of the Black Sea as evidenced by shells and the "bones of great fishes" still found in the mountains. In Codex Leicester, fol. 10v, he wrote that "above the plains of Italy where birds now fly in flocks, were wont to wander large shoals of fish."
The encounter in the cave also may have led to innovations in the composition of Leonardo's artworks. Within a few years of the above entry from Codex Arundel, he drew and painted a number of images in which a grotto or sedimentary rock formations, home to a host of fossils, figure prominently (fig. 3). In the early 1480s he painted the Adoration of the Magi, St. Jerome and the Virgin of the Rocks, all of which feature a landscape made up of sedimentary rocks. Such a setting was traditional for the representation of St. Jerome but unusual for the Virgin. Interestingly, two of these paintings include overhanging rocks that closely recall his notes of 1480 in the Codex Arundel.
The Virgin and Child with St. Anne, painted almost twenty years later, displays even more detailed sedimentary rock. During the years surrounding the creation of this painting Leonardo wrote frequently about the history of the earth, describing in detail the sedimentation processes that built up the layers of rock and led to deposits of fossils. In addition to the Codex Leicester entries, Leonardo made some enigmatic drawings that some have supposed to be fossils (Manuscript Madrid I, fol. 25r); this idea has been supported by recent paleontological evidence (fig. 4).
Although it is certainly possible that Leonardo's description of the cave was colored by his reading of classical poetry, it is essential to consider his work from multiple angles and from a variety of disciplines. A classics scholar may see similarities between Leonardo's great "fish" and passages from Seneca's third book in which the ancient author writes of vast caves containing fish. But a biologist, aware that there are many species of cave-dwelling fish, is likely to make a distinction between Seneca's cave fish and Leonardo's account of the ancient bones of a great "fish," which seems to describe a fossil whale. Pliny, whose Natural History Leonardo owned, wrote of whales, and Leonardo may have drawn on this or other classical sources for his description of the animal's behavior (interestingly some whales do "lash" or slap their fins on the water to stun the fish they are hunting).
It has been argued that Leonardo's studies of fluvial geomorphology, fossils and the metamorphosis of the earth qualify him as one of the earliest observers of subjects that otherwise received little attention from the scientific community until the 18th century. In fact, prior to the appearance of Charles Lyell's Principles of Geology in 1830, the Deluge was the common explanation for the distribution of fossils, a premise Leonardo rejected more than 300 years earlier. It is intriguing to think that the "marvelous thing" Leonardo chanced upon in a cave as a young man set him on one of his many paths of inquiry into nature, and perhaps contributed elements both naturalistic and mysterious to his art.
Fig. 1 Whale rib in La Lisca, less than 20 miles west of Florence.
Fig. 2 Whale fossil excavation in Tuscany at Orciano Pisano.
Fig. 3 Leonardo da Vinci, A rocky ravine, c.1475-80, pen and ink, Windsor, Royal Library 12395. (Royal Collection Trust / © HM Queen Elizabeth II 2012). Similar sandstone formations can be found in the Arno valley in the area traveled by Leonardo as a young man.