1. Introduction

Paleolithic people depicted the surrounding world in a variety of forms; these represent the earliest monuments of art. The significant appearance and spread of the European Paleolithic works of art can be dated to approximately 30 000 BC. and are considered one of the achievements of the Upper Paleolithic cognitive revolution. The artifacts are categorized as cave art or portable works of art. While artistic creations of this type of mobiliary art have also been brought to light in older contexts [such as Bilzingsleben, Germany; Stránská Skála, Bohemia; Leonardi, Italy], the Upper-Paleolithic era has the greatest number of them. The earliest cave paintings were created about 31 000 years ago (La grotte Chauvet-Pont-d’Arc), the youngest ones about 9000 years ago (La grotte de la Mairie). In addition to being esthetically pleasing to our modern eyes, European Paleolithic cave art has also motivated researchers to attempt to "decipher" the meaning and purpose of the artifacts themselves. Since the 1970s when Alexander Marshack’s investigations first appeared in print, astronomy has also played significant role in the study of these, often several ten thousand year-old finds. Although Marshack’s arguments concerning the existence of meaningful astronomical knowledge in the Paleolithic were called into question early on and then contravened ten years ago, his assumptions had a significant influence on the direction of future research and still impacts work being carried out today in scientific circles (Joseph 2011). Therefore, films, scientific books and articles frequently portray this profound interest in astronomy which has been attributed to Upper Paleolithic culture. 2. The Carved Bone Artifacts and the Calendar

The carved-engraved bone plates of mobiliary art were the earliest objects which attracted the attention of researchers. Alexander Marshack (1972) interpreted the various Paleolithic and Mesolithic, mostly portable, objects that bear engraved or painted series of dots or lines as accurate lunar observations. His arguments were based not only on counting the signs but on what he called "microscopic analysis". The interpretation of the markings on various artifacts as notational systems rests on the hypothesis of a slow accumulation of these marks which correlate with lunar or solar motion. Thus he concluded that these artifacts reflect nonarithmetic observational astronomical skills and lore. The most well-known depiction interpreted by him is found on the bone plate about 30 000 years old, from Abri Blanchard (Dordogne, France) which is said to represent the waxing and waning moon positions in serpentine form.

Francesco d’Errico and colleagues developed a different type of methodology (d'Errico 1989). Drawing on experimental archaeology, they compiled a database in an attempt to demonstrate whether the notches represent notational systems or not. After investigating great number of artifacts they concluded that there were some objects which might have depicted parts of a series of complex codes based on the hierarchical organization of information, and using formally differentiated marks. One of these artifacts might be the find from the cave Taď (Drôme, France) whose age is about 10 000 years.

After studying Eurasian portable art the Russian investigator B.A. Frolov also became convinced that these objects were calendars following the monthly motion of the moon and/or yearly solar path, and claimed they were used by early communities. The most well-known bone plate interpreted as a lunisolar calendar is from Ma’lta (Irkutskaya Oblast, Russia).

However, not only has the abstract decoration of small objects been interpreted as a type of calendric notation. On the large, smooth well-worn surface of a rock at Abri de Laussel (Dordogne, France), faint, fragmentary reliefs of several human characters were discovered among them that of a curved standing figure of a female holding a bison horn engraved with 13 strokes. This number is assumed to have a relation to the moon and the depiction to the notion of pregnancy (Joseph 2011). The creators were supposedly aware of the connection between the periodicity of the menstrual cycle and the moon.

Alexander Marshack’s arguments had an impression even on Hungarian researchers. László Vértes, the internationally recognized palaeontologist, published a description of a small artifact made of carved limestone, found in an excavation at Bodrogkeresztúr-Henye, Hungary, in 1963. He claimed that it represented a uterus with lunar calendric notations. The find can be (Vértes 1965) dated to the middle part of the Upper Paleolithic Period and is about 27 000 years old.

The possible existence of a notational system is not in itself evidence for the existence and use of a calendar. According to Francesco d’Errico, Alexander Marshack’s classification was based on Marshack’s own intuition and in reporting his results, Marshack manipulated the number of marks and sequences in order to achieve an accumulation correlated to the motion of the sun or moon (d'Errico 1989). For calendric purposes, the notational system requires the object to have recognizable reference points, some visually distinctive marks (signaling a feast, or regularly occurring phenomena or events taking place during the year, etc.), as is the case with modern calendar sticks. Thus, a series of undifferentiated notches on a surface is not sufficient. None of these distinctive features are found on these artifacts. Moreover, since the objects themselves are quite small, the marks can hardly be differentiated by naked eye. Thus they would have been rather unsuitable for calendric purposes.

Moreover the following question must also be considered: whether there was a need for the owners to have a calendar. Previously, researchers assumed that calendars based on astronomical phenomena were used only by agricultural peoples so that they could know when to perform important activities such as sowing and harvesting. The example commonly cited is Hesiod’s work titled "Works and Days", dated to the 7th century BC. It proves the significant role of the Pleiades’ risings and settings in farming. A number of researchers assume that the western European megalith stone circles (3rd millennia BC) and the even older circular earthworks of Central Europe (5th millennia BC) also had a calendric function. However, this has not yet been clearly demonstrated.

Cyclical movements of celestial bodies, together with the seasons and changes in the weather could have been connected with other periodic changes of importance for hunter-gatherers, such as the timing of the migration of birds and animals, the collection of fruits, berries, etc. According to anthropological research, sky phenomena are also associated with the recurring celebration of important community events. The use of decorative body objects, the increasing emphasis on the burial of the dead, but, most importantly the high-quality, artistic animal and human representations attest to the significant cognitive development of Upper Paleolithic populations (Rossano 2010). Therefore, it could be argued that during this same period, these human cognizers who, according to archaeological research, already showed characteristic symbolic behaviors, might have operated with (simple) calendric systems.

3. Cave Paintings and the Constellations

Interest in the sky is as old as human culture. All peoples have populated the sky with mythical creatures, heroes who played an important role in the life of the community, and figured prominently in their myths and legends. Researchers interested in Paleolithic sky lore use different methodological approaches to explore this possibility. The Spanish investigator Luz Antequera Congregado applies art-history to the study of the paintings; the French researcher Chantal Jčgues-Wolkiewiez uses complex anthropological methods involving astronomical measurement and constellation projection. The German archaeoastronomer Michael Rappenglück approaches the problem with interdisciplinary methodology. And their work is regularly published in scientific journals.

In their search for Paleolithic constellations, the researchers have been inspired particularly by the famous paintings of the Hall of Bulls (La Salle des Taureaux) in the Lascaux Cave (age approx. 15 000 years). Although many of the bison-(and some deer-) representations cover the ceiling, most of the interest was aroused by an especially large figure of a bull. There are six dots arranged in two rows above his shoulder and dots can also be seen on his V-form head. This notational set is generally interpreted as the visualization of the Taurus constellation in its whole shape, together with the "six dots" of the Pleiades and the "spotted" V head representing the Hyadok star cluster.

In his doctoral dissertation Michael Rappenglück (2004) claims that the cave walls reveals not only constellations but also the full worldview of the Paleolithic shamans that inhabited it, concretely, in the paintings on the walls of the gallery named "the Shaft of the Dead Man" (Le panneau de l’homme blessé) in the depth of the cave itself. The night sky offered a particular spectacle in the middle of the midsummer night, about 14-15 000 years ago. Three close bright stars (Vega, Deneb and Altair or Rotanev) as circumpolar stars, forming a triangle revolved around the North Pole which pointed at δ Cygnus lying on the Milky Way. Rappenglück assumes that all these elements had made such a deep impression on the shaman of the Paleolithic community that he immortalized the spectacle by incorporating its coordinates in a drawing of his own body. The eyes of the figures form the Summer Triangle, the standing shaman figure serves as reference line, whilst the bird-headed ‘shaman stick’ points to the North Pole.

Interpreting pictorial elements as star groupings is not confined to the Lascaux cave. One of the 21 000 year-old drawings of the Tęte-du-Lion cave (Ardčche, France) depicts a bison cow with 21 dots arranged in a curved line. A group of 7 dots can also be found on the animal’s body, not far from a single point. Rappenglück argues that this picture set represents the Pleiades with the bright star Aldebaran and includes a symbol of the moon cycle.

A number of well-known representations of the Pleiades are actually quite similar to the group of dots mentioned above. Since it has a rather compact shape, this is a star cluster found in many cultures, although with different names. Some peoples saw it in oblong shape such as in the representation of the Mesopotamian boundry stones (kudurru) and seals whilst others arranged the stars in a circular fashion as is the case of the famous buckskin map of the North American Skidi Pawnee Indians. Moreover, the six-dot-circular group on the Bronze Age Nebra disc is also likely to stand for the Pleiades (Pásztor 2010).

At the El Castillo cave in Spain there are human hands painted on the walls. Their age is about 13 000 years. Beside one hand a semicircle of seven points can be seen. According to Rappenglück’s interpretation they represent the Northern Crown constellation (CrB) in lower culmination. The German researcher claims that the joint depiction of the hand and the dots signals how to find the position and direction of the North Pole in the sky.

4. The Origin of Constellations

The investigation of the origin of star groups is one of the most discussed themes in the history of Western astronomy. Their "birth" and history can only be examined broadly as it is difficult for research on this topic to be examined with a narrow geographic focus.

The first known Greek description of the now classical constellations and among them the Pleiades was made by Eudoxus of Cnidus around 370 BC. However, his description of the stars and constellations form the basis of a great poem called Phenomena, written about 270 BC by Aratus of Soli. Parts of the description are believed to date from at least a thousand years earlier. This ancient Greek system is assumed to have developed gradually and from multiple traditions. A well-established Mesopotamian list of stellar constellations, among them the twelve zodiacal signs and four associated constellations, was taken over by the Greeks as late as around 500 BC when astrology rapidly started to spread in the Classical World (Rogers 1998). The Perseus group associated with a classical legend has been proven to be of clear Greek origin and was placed in the sky between 1250 and 480 BC. (Wilk 2000).

Some of Eudoxus’ constellations have been shown to be of non-Mesopotamian and non-Greek (or pre-Greek) origin. Among these groups of star figures, there would have been enormous serpents and bears and giants that were eventually integrated into the classical sky map (Rogers 1998).

In early prehistoric Europe interest in the night sky might have been stimulated by rites related to initiation or vision quests to the Upper World. During the initiation rites the candidates might have looked at and followed the life of cultural heroes, retelling their exploits, projecting their deeds and stations onto the sky, like in Australia. Each constellation, representing heroic actions, helped the participants of the rites remember the story-line itself. So many communities, so many stories, thus ‘countless’ different constellations populated the celestial landscape, although there are star groups belonging to different cultures which are constituted by the same bright stars as their compact formations are easy to recognize. These include the Great Bear and Orion constellation, the Milky Way and also the Pleiades. However the latter is not viewed as an independent constellation; it is the part of the Taurus.

The strange creatures of the classical map might have played roles in pan-European Bear Ceremonialism and were projected onto the sky as the Spirit Animal Guardians of the hero, while other constellations acted as stations that marked the ritual path of the shaman and/or initiate’s own vision quest to the Upper World. A research project called "Hunting the European Sky Bears" has investigated a set of folktales known as "Bear Son Tales", found in all the languages of Europe (Frank and Bengoa 2001). The results of this project suggest that these orally transmitted tales along with the related performance art, dances and animal miming still can be found as part of the cultural and linguistic repertoire of Euskal Herria, the Basque region of the Pyrenees in Europe. It proposes that the astral counterparts of the half human and half bear hero Hartzkume ("Bear Son"), who was placed where we now find Hercules, included not only the circumpolar stars of Draco, Ursa Major and Ursa Minor, but also certain southern constellations as main characters in the stories. Calculations based on the location of the zone of evasion indicate that the time period in which the early Europeans were already conscious of these celestial phenomena can roughly be estimated as between 4000 BC to 2000 BC. The star groups of Bears with Bootes as a hunter may well be much older, dating to before 10,000 BC when North America was populated by the migration across the Bering Strait as both Eurasia and North America share the primeval myth of the sky bears (Gibbon 1964).

Naturally, the constellations or rather groups of stars were used for different purposes. In addition to their use as reference points in establishing the seasons of the year and telling time at night, another reason for creating them could have been the need to take bearings on land and at sea. Consequently, members of prehistoric societies would have acquired a certain level of knowledge and understanding of the celestial landscape.

This was, however, a long process, whose origins reach far back into human history. The creation of zodiacal constellations in Mesopotamia took several millennia according to archaeological finds and written sources. Obviously the same can be assumed for the non- Mesopotamian constellations. This means that one should avoid theories which presuppose a single place and time for developing the classical sky map as was suggested by Maunder, Ovenden and Roy (1984). Moreover, in the case of prehistoric Europe there are no written sources dealing with this process as in Mesopotamia or Egypt. Therefore, methodologically, research should rely on archaeological features and anthropological observations. Without them no scientific certainty can be achieved.

5. Characteristic of the Identification of Paleolithic "Astronomical Depictions"

The dating of constellation figures back to the Paleolithic is based on the assumption that the figures depicted are true representations of the constellations as seen in that time period (Joseph 2011). Quite often the position of the different hypothetical astral depictions is also supposed to be directly equivalent to the real arrangement and the size of the dots represented in the cave painting. It is even argued that the size of the dots corresponds to the brightness of the compound stars. In the case the animal or human figures chosen for analysis by researchers these are ones that have counterparts in the classical star map, which takes for granted both the Paleolithic origin and cognitive continuity of the constellations in question across many millennia.

Arguments against such attempts to identify constellations dating back to the Paleolithic are the followings:

6. Conclusion

Interest in the sky is certainly as old as mankind itself. However, we must exercise caution in our attempts to reconstruct the cognitive processes that were operating in the minds of our prehistoric ancestors as they created these artifacts. Until now no research into prehistoric European cave and mobiliary art has brought about the definitive identification of astronomical knowledge. Rather the hypotheses put forward to date concerning the existence of such astronomical knowledge during the European Paleolithic seem to be grounded primarily on the researchers’ enthusiasm and desire to find such correspondences rather than on the interpretation of genuine, archaeological evidence. Despite this rather negative assessment, we need to recognize the value of the work carried out to this point for it calls attention to new methodological approaches and fields of inquiry and in the process, stimulates others to investigate these questions. This is the path of scientific research.

In conclusion, our inability to give irrefutable proofs for the existence of astronomical knowledge in cave paintings and mobiliary artifacts does not mean that Paleolithic people were not interested in the sky. Celestial phenomena might also have had significant influence on them, like on many other groups and communities around the world. However, it is very difficult to bring to light such "hidden" knowledge for to do so requires, quite inevitably, that interdisciplinary approaches be brought to bear on what is unquestionably a highly complex interpretative task and one for which astronomical calculations may not provide significant insights (Pásztor and Priskin 2011).

Acknowledgments The author would like to acknowledge Annamaria Priskin, a paleontologist and Roslyn M. Frank Professor Emeritus for their essential cooperation.