European Society for Astronomy in Culture SEAC Publications; Vol. 01 Sonja Draxler, Max E. Lippitsch & Gudrun Wolfschmidt Harmony and Symmetry Celestial regularities shaping human culture Proceedings of the SEAC 2018 Conference in Graz Hamburg: tredition 2020 Calendrical Interpretation of Spirals in Irish Megalithic Art Marc Türler Independent scholar, formerly at the Department of Astronomy of the University of Geneva [email protected], [email protected] Abstract: The tumuli of Newgrange and Knowth in Ireland are among the most monumental heritages of the Neolithic era. The megalithic constructions date back to around 3'200 BC, centuries before the completion of Stonehenge and the Egyptian pyramids. Passageways inside the mounds have been shown to be aligned such as the rising sun illuminates the interior chambers on the winter solstice at Newgrange and around the equinoxes at Knowth. Many of the kerb and interior stones are covered with petroglyphs, in particular with spiral motifs. Despite several attempts to classify and interpret them, they remain enigmatic. Here we show that some of the most elaborated spirals are likely calendrical representations. We use a new, ‘dynamic’ approach adding a temporal dimension to the rock art. We identify in the detailed spiral motifs up to five different manifestations of the solar and lunar cycles, which could easily be observed in prehistoric Ireland. Corroborating evidence comes from adjacent motifs or a special location of the stone. Although the work is speculative by nature, many clues give confidence in the interpretation. If correct, it would imply that one or a few individuals developed skills for celestial observations, the design of complex motifs and their preservation on the rock. This resembles a scientific process, but is more likely the expression of a ritual engagement with the sky. Keywords: archaeoastronomy; calendars; cycles; gnomon; Ireland; Knowth; Neolithic; Newgrange; petroglyphs; rock art; spirals; symbols Introduction meaning, but one would then expect more repetition in the motifs. On the contrary, every decorated stone has a unique Newgrange and Knowth are two large megalithic mounds composition of simple elements such as triangles, lozenges, both located in the bend of the river Boyne not far from arcs, concentric circles, spirals, chevrons, and wavy lines Dublin. Covered with grass and encircled by kerbstones, (e.g. Shee Twohig, 1981). they used to be considered as graves and called passage tombs, because one or several corridors lead to interior In the early 1990s emerged the idea that the megalithic art chambers. Although there is evidence for burial human could be related to visions during altered states of remains (O’Kelly, 1982; Eogan, 1986), the astronomical consciousness (Lewis-Williams and Dowson, 1993; orientation of the passageways suggests that these Dronfield 1995). This was deduced from the analogy of monumental constructions were not primarily tombs (e.g. some of the prehistoric motifs with drawings performed O’Callaghan, 2004; Murphy, 2012). Their design aims to when taking drugs. However, whereas drawing dots, let sun rays illuminate the chamber of Newgrange at sunrise zigzags and lines on a sheet of paper can be done in such a on the winter solstice (Patrick, 1974; Ray, 1989) and the state of mind, engraving them on the rock with stone tools two corridors of Knowth at sunrise and sunset near the time seems almost impossible. Furthermore, the complexity of of the equinoxes (Eogan, 1986; Ruggles, 1999; Prendergast some patterns make them unlikely to reflect a vision in a & Ray, 2017). state of altered consciousness. The effort put into the conception and painful engraving of complex symbols, On the abstract nature of the megalithic art such as double and triple spirals, suggests a higher intention than either decoration or recording of hallucinations. Many of the kerb and interior stones at Newgrange and Knowth are covered with petroglyphs (O’Kelly, 1982; The art most likely represents celestial manifestations Eogan, 1986). This megalithic art is dominantly non- figurative and often geometric, although there may be rare In the quest of the hidden meaning of the abstract art, the exceptions of anthropomorphic figures and elements of most promising route seems to be an association with figuration within the abstract art (O'Sullivan, 1997; Robin, celestial manifestations. Indeed, the regular cycles of the 2012). Such an art could be purely ornamental without any sun, the moon and the stars must have fascinated mankind 1 Calendrical Interpretation of Spirals in Irish Megalithic Art already in prehistoric times. At least in the Neolithic era, The difficulty until now to interpret the art might have been settled communities would most likely have attached a to look at it in a static way, simply as two dimensional great importance to these cycles, because they are linked to pictures. The creation of the motifs is instead a dynamic the passage of seasons affecting their agricultural life. process. Including this temporal component could reveal Another clue is that the most richly engraved stones are not new insights. For instance, when you represent a filled placed randomly, but are oriented towards specific celestial triangle (p) or a filled lozenge (t), there is more material points. This is particularly evident in Newgrange with to remove with a series of pick-marks at the centre of these kerbstones K52 and K67 oriented towards the direction of geometric figures than on their left and right sides. The sunrise and sunset at the summer solstice (Brennan 1983: engraving process therefore takes more time at the centre. 192). Another hint is the presence of several fan-shape A dynamic interpretation of both signs is that they could petroglyphs evoking sundials, in particular at Knowth on represent a variable period of time with an increase the flat top of kerbstone K7 and forming the central motif followed by a decrease in duration. Such signs could for of kerbstone K15, sometimes called the ‘sundial stone’ instance represent the variable length of daylight from (Brennan, 1983; Harley, 2009). Finally, the intentional winter to summer and back to winter. More generally, they alignment of the passageways with the direction of sunrise could express the abstract notion of increase followed by or sunset on specific days of the year is a clear evidence of decrease or growth followed by decay, as can be observed the importance of annual cycles to this Neolithic in nature: sunrise and sunset, waxing and waning moon community. In such a context, it would be natural that at phases, rising and ebbing tides. Symbolically, this could least part of the art is also related to astronomical also reflect the cycle of life with the birth and death of manifestations. This possibility was explored intensively flowers, trees, animals, and humans. This special meaning by Brennan (1983) and Thomas (1988), who presented would explain why triangles and lozenges are so much interesting ideas, some of them rather convincing, others more frequent in Irish megalithic art than other geometric much less. The most explicit representation of astronomical forms such as squares and rectangles (e.g. Shee Twohig, cycles seems to be on kerbstone K52 at Knowth. This so- 1981). called ‘calendar stone’ shows a succession of 22 crescents or horseshoes completed by 7 circles. Their arrangement in Similarly, it is not enough to just look at a complex spiral an ellipsoid leaves little doubt that they represent the moon motif, but one really needs to follow its pattern with the phases over 29 days, i.e. the synodic month (Brennan, finger to feel the longer time it took the artist to engrave 1983; Prendergast, 2017). The associated wavy line has them as the circles enlarge away from the centre. In a further been successfully interpreted by Brennan (1983) as dynamic interpretation this could be a representation of the a count of months to synchronise the lunar and annual abstract notion of an increasing duration over several cycles. Besides this example and possibly some other less cycles. A typical example is the seasonal increase of robust claims, the vast majority of the rock art could not yet daylight over several lunar cycles. The frequent association been convincingly and coherently interpreted. of filled triangles or lozenges with spirals, which is very obvious on all three richly decorated kerbstones of This article aims to reconsider the idea that a fraction of the Newgrange (K1, K52, and K67), would find an explanation megalithic art is a representation of astronomical with such a dynamic approach of the art. All three motifs manifestations. This is done with a new, ‘dynamic’ could represent the abstract notion of a duration changing approach of the art, which is shown in the next section to with time, such as daytime over a year. be promising. We then present a set of observable properties of astronomical cycles, which could have been easily observed by Neolithic people. For the actual interpretation, we focus our analysis on spiral motifs of the Bend of the Boyne, which seem to have been at the origin of a very enduring pictorial tradition (Morrison, 2005). There are several reasons for this choice: 1) spirals are very typical of the art at Newgrange and are also often present at Knowth; 2) a spiral traces a series of circles alike the apparent movement of the celestial bodies in the sky; and 3) the spiral motif seems to be the most complex design of the megalithic art with many variations from the simplest spirals to complex S-shaped, double and triple spirals. For a set of five specific spiral motifs, we identify characteristics of the design, which appear to match the seasonal, celestial manifestations of the sun and the moon. We then discuss the validity of the interpretation and put the study in context with respect to other spiral petroglyphs and earlier work.