Abstract The submerged sill in the Strait of Messina, which is located today at a minimum depth of 81 m below sea level (bsl), represents the only land connection between Sicily and mainland Italy (and thus Europe) during the last lowstand when the sea level locally stood at about 126 m bsl. Today, the sea crossing to Sicily, although it is less than 4 km at the narrowest point, faces hazardous sea conditions, made famous by the myth of Scylla and Charybdis. Through a multidisciplinary research project, we document the timing and mode of emergence of this land connection during the last 40 kyr. The integrated analysis takes into consideration morphobathymetric and lithological data, and relative sea-level change (both isostatic and tectonic), resulting in the hypothesis that a continental land bridge lasted for at least 500 years between 21.5 and 20 cal ka BP. The emergence may have occurred over an even longer time span if one allows for seafloor erosion by marine currents that have lowered the seabed since the Last Glacial Maximum (LGM). Modelling of palaeotidal velocities shows that sea crossings when sea level was lower than present would have faced even stronger and more hazardous sea currents than today, supporting the hypothesis that earliest human entry into Sicily most probably took place on foot during the period when the sill emerged as dry land. This hypothesis is compared with an analysis of Pleistocene vertebrate faunas in Sicily and mainland Italy, including a new radiocarbon date on bone collagen of an Equus hydruntinus specimen from Grotta di San Teodoro (23–21 cal ka BP), the dispersal abilities of the various animal species involved, particularly their swimming abilities, and the Palaeolithic archaeological record, all of which support the hypothesis of a relatively late land-based colonization of Sicily by Homo sapiens .

Archaeochronology seeks to establish absolute or relative dates for archaeological or paleoanthropological events. Therein, the scale, or the temporal resolution attainable, changes dramatically over the total time for human cultural and biological evolution. For radiometrically based dating methods, the half life (half lives) isotopic abundances, and contamination limit the intrinsic dating range, whereas factors, such as radiation dose, saturation effects, diffusivity, and chemical rates, limit other absolute archaeochronometers. As technology improves, however, precision usually increases, while the intrinsic dating limit can often be extended, thereby enhancing the scale. Even were the dating methods significantly more precise, contamination or sample degradation often further restrict a method’s utility, while the number of sites preserved diminishes the older they are. Moreover, the archaeological “distinctiveness” decreases, perhaps due to the imprecision in the dating methods, but possibly, because the tempo in human cultural and biological evolution has incrased exponentially. Increasingly finer archaeochronological scales have significantly altered archaeological paradigms, in all phases of hominid biological and cultural evolution from African Australopithecus’ skeletons to North American Homo sapiens sapiens’ longhouses. While multiple concordant dates may resolve the dating problem presented by a single method, often sample instability affects all the applicable methods. Frequently, relative methods can constrain the absolute date. The accuracy for any new method or a new application to different sample materials must be rigorously tested under controlled conditions for concordancy with other established methods. Concordancy tests, intra-and intersite correlation all require extensive knowledge about the inherent limitations in the different methods. Ultimately, it rests with the archaeologist to thoroughly understand those limitations, and the archaeochronologist to fully understand the archaeological problems.