Changes

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 drifted by one day every 23.7 years.<ref name="Olmsted"/><ref>The amount of drift can be used to estimate the age of the calendar. For Samhain to move from the December-January period to November suggests that the calendar was in use for about 1,300 years. Pliny writes that Celtic months started on sixth day of the lunar cycle. This suggests that the calendar had already accumulated a thousand years worth of drift in his time, according to Olmsted.</ref>

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 drifted by one day every 23.7 years.<ref name="Olmsted"/><ref>The amount of drift can be used to estimate the age of the calendar. For Samhain to move from the December-January period to November suggests that the calendar was in use for about 1,300 years. Pliny writes that Celtic months started on sixth day of the lunar cycle. This suggests that the calendar had already accumulated a thousand years worth of drift in his time, according to Olmsted.</ref>

===American Halloween===

===American Halloween===

Although Halloween is often connected to Irish immigration, the holiday entered mainstream American culture in the late 19th century and in Protestant settings, as Karen Sue Hybertsen shows in her thesis.<ref>Hybertsen (1993), p. 10.</ref> This suggests that Victorian revivalism is a more likely source of the holiday than Irish immigration.

Although Halloween is often connected to Irish immigration, the holiday entered mainstream American culture in the late 19th century and in Protestant settings, as Karen Sue Hybertsen shows in her thesis.<ref>Hybertsen (1993), p. 10.</ref> This suggests that Victorian revivalism is a more likely source of the holiday than Irish immigration.