Þorláksmessa ([ˈθɔrlauxsˌmɛsːa], Mass of St. Thorlac) is an Icelandic holiday celebrated on December 23. It is a celebration in honor of Þorlákur Þórhallsson, bishop of Skálholt, who was canonized and recognized as the patron saint of Iceland in 1984, centuries after his death on December 23, 1193. The day is also celebrated in the Faroe Islands, where it's called Tollaksmessa.
In modern times, Þorláksmessa has become part of Christmas: on the 23rd, many people finish decorating their houses and the Christmas tree, and buy Christmas presents. On Þorláksmessa evening in Reykjavík, many go out and stroll down Laugavegur.
In Iceland it is customary to eat buried and fermented skate along with potatoes on Þorláksmessa; in recent years, this custom is something that most people do not like the smell off, but eat because this is a celebrated tradition. The ammonia-infused odor of fermented skate is quite strong, similar to that of hákarl.