December 13, St. Lucia Day, also known as the Festival of Light, is a day of celebration in Sweden, in the spirit of Advent and Christmas. Young girls are dressed in white robes with a red sash, with one girl selected as "Lucia" who wears a crown of lit candles (or battery powered ones), the others carrying a single candle. Processions with singing and revelry abound.
At home, the eldest girl dresses up in robe, sash, and candle crown, and delivers coffee and lussekatter, or S shaped saffron buns to her parents for breakfast.
Saffron bun recipe: https://www.simplyrecipes.com/recipes/st_lucia_saffron_buns/
https://infogalactic.com/info/Saint_Lucy%27s_Day
Ember Days follow St. Lucy's Day traditionally:
The Ordo Romanus fixed the spring fast in the first week of March (then the first month), thus loosely associated with the first Sunday in Lent; the summer fast in the second week of June, after Whitsunday; the autumnal fast in the third week of September following the Exaltation of the Cross, September 14; and the winter fast in the complete week next before Christmas Eve, following St. Lucy's Day (Dec. 13).
https://infogalactic.com/info/Ember_day