In ancient Rome, the [dies] Aquilae natalis was the "birthday of the eagle", the anniversary of the official founding of a legion.
Anniversaries of nations are usually marked by the number of years elapsed, expressed with Latin words or Roman numerals.
In these instances, the name of the anniversary is generally derived from the Latin word(s) for the respective number of years.
Etiquette in Society, in Business, in Politics and at Home by Emily Post, published in 1922, contained suggestions for wedding anniversary gifts for 1, 5, 10, 15, 20, 25, 50, and 75 years.
[12] Wedding anniversary gift suggestions for other years were added in later editions and publications; they now comprise what is referred to as the "traditional" list.