Shieldmeet

Shieldmeet was the equivalent of a leap year day in the Calendar of Harptos (every 4 years, starting year 0, 4, ... 1496, etc), occurring once every four years, adding a day after the festival of Midsummer and before Eleasis 1. Traditionally the day was used for fairs, bazaars, musical and theatrical performances, and tournaments of skill and magical ability. Nobles usually held court to hear the petitions of their people and to make or renew trade pacts, alliances, and agreements.
Shieldmeet was known as Cinnaelos'Cor (also seen as Cinnaeloscor), "the Day of Corellon's Peace" in elvish and marked the end of an aeloulaev and the beginning of a new one in the elven Aryselmalyn calendar.