Winter solstice
While this does not hold for our current Gregorian calendar, a discrepancy of 8 days would have been the case in the Julian calendar during the 14th century, resulting in Winter solstice falling on 13 December. With the original adoption of the Gregorian calendar in the 16th century the discrepancy was 10 days and had increased to 11 days in the 18th century when Scandinavia adopted the new calendar, with Winter solstice falling on 9 December.