A tradition is a story or a custom that is memorized and passed down from generation to generation, originally without the need for a writing system. Tools to aid this process include poetic devices such as rhyme and alliteration. The stories thus preserved are also referred to as tradition, or as part of an oral tradition. For example, it is now a tradition to have a Christmas tree to celebrate Christmas.
Although traditions are often presumed to be ancient, unalterable, and deeply important, they are often much less "natural" than is often presumed. Many traditions have been deliberately invented for one reason or another, often to highlight or enhance the importance of a certain institution. Traditions are also frequently changed to suit the needs of the day, and the changes quickly become accepted as a part of the ancient tradition. A famous book on the subject is, The Invention of Tradition, edited by Eric Hobsbawm and Terrence Ranger.
Some examples include "the invention of tradition" in African and other colonial holdings by the occupying forces. Requiring legitimacy, the colonial power would often "invent" a "tradition" which they could use to legitimize their own position. For example, a certain succession to a chiefdom might be recognized by a colonial power as traditional in order to favour their own favourite candidates for the job. Often these inventions were based in some form of tradition, but were grossly exaggerated, distorted, or biased toward a particular interpretation.
Other traditions that have been altered through the years include various religious celebrations, for example Christmas. The actual date of Jesus' birth does not coincide with December 25 as in the Western Church. This was a convenient day for it to be held on so as to capitalize on the popularity of traditional solstice celebrations.
In the Roman Catholic Church, traditionalism is the doctrine that tradition holds equal authority to holy scripture. In the Orthodox Church, scripture itself is considered a part of the larger tradition. These are often condemned as heretical by Protestant churches.
Traditionalism is at its best a desire to protect useful and hard-won traditions, and at worst a form of chauvinism for the past based on nostalgia.
Traditionalism may also refer to the concept of a fundamental human Tradition present in all orthodox religions and traditional forms of society. This view is put forward by the Traditionalist School.
In archaeology a tradition refers to a series of cultures or industries which appear to develop on from one another over a period of time. The term is especially common in the study of American archaeology.
Article on the "authenticity" of tradition (http://www.polity.co.uk/giddens/pdfs/Tradition.pdf)