Changes

[[File:Halloween skull.jpg|thumb|left]]The Irish adopted the Julian Calendar around AD 450. Significant dates may have transferred from the Celtic calendar. A Celtic lunisolar calendar has been reconstructed from fragments of two second century calendars, one found in the French town of Coligny and the other in Villards d'Heria. The first month on this calendar is called ''Samonios''. This month is cognate with Samhain and contained the winter solstice.<ref name="Olmsted">Olmsted, Garrett (1992). ''The Gaulish calendar: a reconstruction from the bronze fragments from Coligny, with an analysis of its function as a highly accurate lunar-solar predictor, as well as an explanation of its terminology and development,'' p. 193.</ref>

[[File:Halloween skull.jpg|thumb|left]]The Irish adopted the Julian Calendar around AD 450. Significant dates may have transferred from the Celtic calendar. A Celtic lunisolar calendar has been reconstructed from fragments of two second century calendars, one found in the French town of Coligny and the other in Villards d'Heria. The first month on this calendar is called ''Samonios''. This month is cognate with Samhain and contained the winter solstice.<ref name="Olmsted">Olmsted, Garrett (1992). ''The Gaulish calendar: a reconstruction from the bronze fragments from Coligny, with an analysis of its function as a highly accurate lunar-solar predictor, as well as an explanation of its terminology and development,'' p. 193.</ref>

The Coligny calendar gives the length of an average solar year as 365.24 day, the same length that the Julian calendar gives. If uncorrected, it would drift by three days every four hundred years. If Samhain was once a month that contained the winter solstice, it had drifted so that by AD 450 it corresponded roughly to November. This suggests that the Celtic calendar had been in use for about 1,300 years at that point.<ref name="Olmsted"/>

With a leap day every five years, the Coligny calendar gives the length of a solar year as 365.20 days. Since the true length is 365.2422 days, the calendar drifts by one day every 24.7 years. If Samhain was once a month that contained the winter solstice, it had drifted so that by AD 450 it corresponded roughly to November. This suggests that the Celtic calendar had been in use for about 1,300 years at that point.<ref name="Olmsted"/>

====Bonfires====

====Bonfires====