ADVENT
(Latin ad-venio, to come to)

According to present [1907] usage, Advent is a period beginning with the Sunday nearest to the feast of St. Andrew the Apostle (30 November) and embracing four Sundays. The first Sunday may be as early as 27 November, and then Advent has twenty-eight days, or as late as 3 December, giving the season only twenty-one days.


It cannot be determined with any degree of certainty when the celebration of Advent was first introduced into the Church. The preparation for the feast of the Nativity of Our Lord was not held before the feast itself existed, and of this we find no evidence before the end of the fourth century, when, according to Duchesne [Christian Worship (London, 1904), 260], it was celebrated throughout the whole Church, by some on 25 December, by others on 6 January. Of such a preparation we read in the Acts of a synod held at Saragossa in 380, whose fourth canon prescribes that from the seventeenth of December to the feast of the Epiphany no one should be permitted to absent himself from church.


In 650 Advent was celebrated in Spain with five Sundays. Several synods had made laws about fasting to be observed during this time, some beginning with the eleventh of November, others the fifteenth, and others as early as the autumnal equinox.


This north German advent wreath came to scandinavia through Denmark.

It was known already as early as 1900, where the "Adventister" come from. In 1915, the priest at St. Nicolaj church was given one for the church, and every year after, it was hung up.

The florentists started selling it in 1939 - 1940, which made it known all over the country. During the occupation, more and more homes started using them during the last weeks before Christmas, starting on the first Sunday. It became a custom to light candles through the darkest time of the year, and the christmas stamp for 1946, had a picture of an advent wreath with 4 candles and red ribbons on.

In most catholic communities, however, violet ribbons are used instead.

From  http://www.newadvent.org/cathen/01165a.htm