In the early 17th century, sailors would gather for a final banquet before setting off on a long 6-month expedition to Iceland to fish for herring. Shipowners offered their sailors the "foye", a meal and feast traditionally held in estaminets in their honor.
As many sailors didn't return from this perilous fishery, they also received half their pay, which they spent during the 3 joyeuses, the Lenten period between Ash Wednesday and Shrove Tuesday.
The festival then known as "Visscherbende" (fishermen's band in Flemish) gradually became associated with Catholic festivities, and was transformed into a carnival with, in particular, the tradition of dressing up in the dresses of sailors' wives and adorning their hats with flowers.