There are very few holidays celebrated throughout the Alliance, whereof these are a few:
Day of the New Century
Celebrated on the first day of each year, the Day of the New Century is a holiday recognized on the Alliance calendar. The tradition began at the beginning of the 4th century in the 5th Age, when the king of Calabria decided to create a new holiday to uplift the spirits of his people. Times were hard, and people would look for any excuse to celebrate. So the king (who happened to be turning 54 that year) decreed that this new century would be the greatest ever for the people of Calabria, and so starting on the first day they would celebrate it, each and every year. The concept of celebrating the new century every year spread like wildfire throughout the Alliance, that it quickly became an inter-dimensional holiday.
Heart’s Day is a holiday that finds its roots in the Aten Nations. An accurate translation continues to elude scholars and linguists, but the original Aten day may actually pre-date the Empire of Roads. In the Aten tongue, the name means roughly “to champion a love so strong that two hearts become one”. Evidence suggests that in the ancient times this was a solemn occasion upon which to honor couples who had been married more than two centuries. In more modern times (to the Aten, ‘modern times’ are defined as post-Mage Wars), it has evolved into a sort of celebration of love. Different regions celebrate it different ways, and few humans even realize it is not a human holiday at all, but in fact an extremely ancient Aten day.
The Heritage Festival began during the Kamian Succession Wars as a way for war refugees to celebrate and continue to honor their customs and cultures. By the mid Sixth Age, it was celebrated all over the Alliance, even in corners not touched by the war (which was still going until the mid-to-late Age). Perhaps the largest celebration of the festival takes place anually in Arindell, which has the most diverse population in the entire verse. The holiday takes place on the 29th and 30th of the 9th month of the year, with celebrations traditionally lasting all night. See Visuban Cluster for a variation of this festival.
Day of Dawn's Reflection
One of the Alliance Holidays: the Day of Dawn’s Reflection celebrates the day when the old Gudersnipe Army and the armies of Eieber, First Pendragon of Slayer Dragons, avoided going to war. According to legend, a thick fog descended over the battlefield before the two armies could draw swords, and Eieber found himself back-to-back with Laytami, the later founder of the Gudersnipe Foundation. Neither knowing who the other was, the two leaders got to talking, discussing old battles and reflecting on the events that had led them to that day. They spoke vaguely, each not to reveal himself. If they had known they were the leaders, they would surely have fought despite the fog. They spoke quietly all night, and in the morning when the fog burned away, and the two leaders finally glimpsed each other, both decided they were not so different after all, in that Eieber dreamed of a free world where no one had to live in fear, and Laytami only really wanted to end the Mage Wars. Ultimate power was the goal of neither, and that day they exchanged trinkets to honor their new agreement. Together, the armies of Laytami and Eieber ended the Mage Wars, and began the Golden Age. Originally the Day of Dawn’s Reflection was observed by reflecting on one’s past conflicts; but in more recent eras has become synonymous with Christmas, which is generally observed by exchanging gifts.
The Day of Dawn's Reflection is celebrated on the 25th day of the 12th month, or the closest analogue in outlying regions.
Wash Day began as a specifically Atayan holiday, though similar celebrations were common throughout the region and similar civilizations off-world. Wash Day is held on the last day of fall, the final day before winter. On the Atayan calendar(eventually adopted by the Alliance), this is also the last day of the year.
The specific purpose of the holiday is rooted in Atayan funerary customs and mourning rituals. Among the Atayans, it was considered very difficult to let someone go whom you owed a debt to or held a grudge against. With many deaths often coming in the winter months, and most Atayans being largely snowed in to their homes, it was an important cultural touchstone to end the year without any regrets. Traditionally on Wash Day, all debts were forgiven and all disputes settled, with the slate being "wiped clean".
Intertwention Day is a New Day era holiday with roots in the Long Night. The festival is observed three times a year, whenever the 13th day of the month falls on a friday. According to the calendar adopted by the new Alliance, this happens in the 6th, 9th, and 12th months of the year. The different dates are named for the seasons, with Spring, Summer, and Winter days. Traditionally, Summer Intertwention Day is the most celebrated as it happens shortly after the Alliance schoolyear resumes.
The exact origin, and even meaning of the name, are lost to history. The celebrations started sometime in the last thousand years or so of the Long Night, and may in fact have been dozens of unrelated holidays. By the New Day era, the holiday had progressed to it's current form.
According to legend, when Arindell was first resettled, the many peoples brought together to populate the new city had several different ideas about when and how to celebrate Intertwention Day. All anyone could agree on was that it had to be held on a Friday on the thirteenth day of the month. Since this happened three times per year, Conri Jusenkyou declared all three dates to be valid.
By the end of the first century N.D., Intertwention Day had come to be associated with three things: costumes, candy, and getting scared. Some traditions held that each occurrence should be devoted to one of the three, but this is believed to be a modern invention. So little is actually understood about the holiday that its hard to draw any real conclusions.
Somewhere around the end of the first century, it became primarily associated with children, and specifically giving those children large quantities of candy, but it has always been a holiday for everyone.