What is "fastelavn"

Fastelavn is the name for Carnival in the historically Lutheran nations of Denmark, Sweden, Norway, Iceland and the Faroe islands which is either the Sunday or Monday before Ash Wednesday. Fastelavn is related to Roman Catholic tradition of Carnival in the days before Lent, but after Denmark became a Protestant nation, the festival became adopted certain distinctives. This holiday occurs the week before the Christian penitential season of Lent, culminating on Shrove Tuesday, the day before Ash Wednesday, the first day of Lent. In it, children dress up in costumes and gathering treats for the Fastelavn feast. The holiday is generally considered to be a time for children's fun and family games.