Who are we?
13 Yule Lads live in Iceland, the sons of the old trolls Grýla and Leppalúði. Grýla and Leppalúði keep a pet, a wicked cat, which may sometimes catch children. Grýla, who is big and formidable, was said to collect the naughty children in a sack and take them home to eat for Christmas dinner. If a child is naughty, Grýla finds out immediately. Grýla can't lay her hands on good children.
An old tradition in Iceland is, that 13 days prior to Christmas the Yule Lads start coming down from the mountain one each night. Children in Iceland place their best shoe on their windowsill before going to bed and each night a little gift is left in the shoe from the Yule lad that came down from the mountain that night. If the child has been misbehaving, there might be a raw potato left instead.