Thorlák Thórhallsson was a Catholic bishop, prolific writer, and archivist in Iceland. He died on December 23, 1193, and was made the patron saint of the nation in 1984. To honor his memory, Icelanders eat kæst skata, or fermented skate, every December 23. 

As to why the holiday known as Thorláksmessa centers around the pungent fish? Catholics historically abstained from eating meat leading up to Christmas Eve, and in the dead of Icelandic winter, pickings were slim. Skate, however, was available year-round, due to a unique natural preservative. Like the Greenland shark, which ferments into the dish known as hákarl, skate excretes uric acid through its skin. This helps ferment and preserve the fish, but also leads to a heavy ammonia aroma that permeates wherever it’s prepared. Understandably, modern diners are divided on the merits of eating fermented skate at home. Typically, restaurant chefs prepare it. They ferment the skate in a sealed environment for a few weeks, then steam or boil it before serving.

Icelandic families gather over lunch to enjoy the holiday’s signature meat with buttered rye bread and boiled potatoes. Adults wash it all down with Iceland’s favorite schnapps, Brennivín, then continue celebrating into the afternoon, followed by a rest in the early evening. When merrymakers rally to visit with friends, no one worries about stinking of skate—everyone’s in the same boat.