Hannibal, with his elephants, crossed the Alps and descended on the plains of northern Italy and over the course of the next 12 years fought a series of major battles with the Romans. In 2011 he was actually at the gates of Rome, and had defeated Roman armies and was a potent threat – but within a few years he had retreated to the heel of Italy, and then to Cathage itself, finally defeated by the Romans – but was there an underlying reason for why his fortunes went into decline? A clue may well lie in the low growth tree ring event of 208BC (see Mike Baillie, A Slice Through Time, Batsford: 1995, page 143).
Mike Baillie, in the same book, appears to have pre-empted the recent Bayesian methodology applied to C14 dates, see Current Archaeology 259 (Oct 2011) which has an article on the Bayesian method, calculating probability by concentrating on the most likely result from a set of all possible outcomes. Baillie associated a low growth episode around 4100BC as the marker between the Mesolithic and Neolithic periods in Britain and Ireland, an event that may have caused a migration of peoples from the continent into our islands. The Current Archaeology article adds the newcomers were responsible for bringing with them domesticated animals, cereals, pottery bowls, leaf shaped arrowheads, ground axe heads, rectangular timber buildings, flint mines, monumental architecture (from the book, Gathering Time: Dating the Early Neolithic Enclosures of southern Britain and Ireland, by Alasdair Whittle, Frances Healy and Alex Bayliss, Oxbow Books:£45).