Have you heard of ev enko s law One hundred and fifty years or more of serious history and good old Dan s dog is the first to pick this tree From what I understood of it and it s rather over my head Mc Carthy has a point However it would be throwing the baby out with the bathwater to adopt his dates before anyone else does It means that every date in a book needs to be Mc Carthy ised And even then I have very serious doubts about the accuracy of the results Mc Carthy s method may give accurate AD dates but I suspect there are problems Take 763 He s content to put Domnall Midi s death in that year just as the historians are but why does AD 763 start with an event dated to 20 November Fair enough that could just be a glitch from the compilation but it could also be that whatever the source was its years did not start on 1 January or March 25 but instead on 1 September Adding that to an article would be WP OR so we won t do that we do when it s Bede s years because people have discussed it in print but this they haven t but we can take it into consideration here when deciding what to do The Chronicle of Ireland was compiled from lots of sources and it would be a reasonable bet that even if most or nearly all of them started the year on 1 January some would have done so on 25 December some on 1 September and some on 25 March Even if Mc Carthy s system is perfect you can only be entirely confident about the year if the event falls between 25 March and 31 August If we can date events to within a year either way that s good if we can date events in the 7th century to within 2 or 3 years that s marvellous If it were me I d go with historian dates i e what Byrne Charles Edwards and the rest say and add Mc Carthy s corrections in a footnote which is what is done with Penda of Mercia and other C7th Anglo Saxons where there is a similar but smaller problem We can ask for outside opinions people like Talk