A Lunisolar Calendar is hidden within the Atlantis story according to a paper presented to the 2008 Atlantis Conference by A. Pliakos. Lunisolar calendars have been in use since ancient times in many cultures, indicating the phases of the moon as well as the time in the solar year.

    Pliakos believes^[750.631] that Critias 119 d2-d4, which refers to the convening of the Atlantean kings every five and six years, contains a previously unknown lunisolar calendar of 11 years duration with an accuracy of 0.09 days per year. As he also claims that it could have been applied in both 9600 BC AND 1200 BC, it cannot be used to date the time of Atlantis. However, he points out that this 11 year lunisolar calendar is in conformity with the development of calendars generally adding to the improbability of the Atlantis story being an invention.