Revisiting the 5000-Year-Old Tally at Mnajdra, Malta

The pillars at the entrance of the inner apse of one of the cluster of Neolithic temples at Mnajdra, Malta display rows of drilled holes which have been interpreted as a tally of days. Furthermore, it has been proposed that the number of holes in the rows on the east pillar coincides well with a sequence of intervals between the heliacal rising of bright stars or star groups. Is this remarkable correspondence simply a chance occurrence, or do the drilled holes represent material evidence of deliberate time reckoning by means of heliacal star risings in the Neolithic age? This question has led to the statistical investigation described in this paper, which takes into account the heliacal risings of all stars of magnitude 2.0 or brighter visible from Malta 5000 years ago as well as the Pleiades and the Hyades star clusters, which attracted the attention of other ancient cultures. The paper presents and discusses the method used and the challenges involved in the investigation. The results show that with a tolerance of ±1 day for uncertainty in the calculated heliacal rise days, the probability of achieving an exact correspondence between a random ordering of the tally and a series of star rises is 0.0014. With a wider tolerance of ±2 days the probability is 0.011. The final section discusses the significance and implications of these results.