Baldur's mother was the Norse goddess, Frigga. When Baldur was born, Frigga made each and every plant, animal and inanimate object promise not to harm Baldur. But Frigga overlooked _________ - and the mischievous god of the Norse myths, Loki, took advantage of this oversight. Ever the prankster, Loki tricked one of the other gods into killing Baldur with a spear fashioned from ______. The demise of Baldur, a deity in the Norse myths, brought winter into the world, although the gods did eventually restore Baldur to life. After which Frigga pronounced the _______ sacred, ordering that from now on it should bring love rather than death into the world. What custom/tradition origianted?