Calendar

The current system of 12 months and 4 seasons was developed during the early years of the Tevinter Imperium (with some influence from the elves); indeed, the primary seasonal holidays have remained unchanged during much of the time since, the only exceptions being the widely celebrated Chantry holidays that became almost universally used after the Second Blight. Each month has a High Name (the original, official Imperial name used primarily by courts and scholars) and a Low Name (the name used by commoners and merchants) and an even 30 days. The five “annums,” or annual holidays, mark the official transition between seasons and the beginning of the year; these are not the only holidays celebrated, but they are the only ones that exist without a month of their own.
==Calendar and Holidays==
*Holiday -- First Day: The beginning of the year, this holiday traditionally involves many visits to one’s neighbors and family (this was once to “check” to make sure everyone was alive at least once a year in remote parts) and a town gathering to commemorate the year past (often accompanied by much drinking and merriment).
*Month 1: High Name -- Verimensis; Low Name -- Wintermarch
*Holiday -- Wintersend: Once called “Urthalis” and dedicated to Urthemial, the Old God of beauty, this holiday has traditionally become a celebration of the Maker. It stands for the end of winter in many lands and often coincides with tourneys and contests that conjure the Proving Grounds in Minrathous (which always has its biggest contests on this day). In most southern lands, this holiday has become a day of gathering for trade, theater, and (in some areas) the arrangement of marriages.
*Month 2: High Name -- Pluitanis; Low Name -- Guardian
*Month 3: High Name -- Nubulis; Low Name -- Drakonis
*Month 4: High Name -- Eluviesta; Low Name -- Cloudreach
*Holiday -- Summerday: Once called “Andoralis” and dedicated to Andoral, the Old God of chains, this holiday is universally celebrated as the beginning of summer, a time for merriment and marriages to take place. Traditionally, boys and girls who are ready to come of age participate in a grand procession in which they cross the settlement in white tunics and gowns and end up at the local Chantry; there they are advised on the responsibilities of adulthood. This is considered a very holy day in Orlais.
*Month 5: High Name -- Molioris; Low Name -- Bloomingtide
*Month 6: High Name -- Ferventis; Low Name -- Justinian
*Month 7: High Name -- Solis; Low Name -- Solace
*Holiday -- Funalis: This holiday was once dedicated to the Old God of silence, Dumat. Since Dumat’s rise during the First Blight, however, this fact has been largely ignored. Now the holiday is invariably known as All Soul’s Day and is supposed to be spent in somber remembrance of the dead. In some northern lands, it is traditional for the population to dress as spirits and walk the streets in parade after midnight. The Chantry has co-opted this holiday to remember the death of Andraste, with fires that mark her burning appearing throughout the community. Plays depicting the tale of her death are also quite common.
*Month 8: High Name -- Matrinalis; Low Name -- August
*Month 9: High Name -- Parvulis; Low Name -- Kingsway
*Month 10: High Name -- Frumentum; Low Name -- Harvestmere
*Holiday -- Satinalia: In many places, this holiday -- once dedicated to the Old Goddess of chaos, Zazikel, but now attributed more to the Second Moon, Satina -- is still accompanied by wild celebration. Celebrants wear masks and lose their inhibitions, and they place the town fool as ruler for a day. In Antiva (Antiva City in particular), this festival lasts for a week or more, followed by a week of fasting. In more pious areas, this holiday is now marked by large feasts. Amid the feasting, it is customary for friends, lovers, and traveling companions to exchange gifts and pranks. This holiday is also known as Feastday.
*Month 11: High Name -- Umbralis; Low Name -- Firstfall
*Month 12: High Name -- Cassus; Low Name -- Haring
==Sources==
Prima Collector's Guide for Dragon Age Origins.