Traditionally thought to be creatures which were forms representing the souls of the dead in transition, similar in belief to many birds and therefore to be treated with great respect. Butterflies in many countries were mainly thought to carry the souls of children that had died before baptism. In Scotland (UK) the appearance of a golden butterfly near someone who is very ill or dying represents good omen possibly indicating recovery although there are many meanings attached to this sighting, one being happiness after death.
Three or more butterflies landing on the same leaf or seen flying after twilight is an omen of death according to European folklore. The colour too contains symbolism similar to many beliefs connected with birds (See Mystical WWW Mystical Birds). White butterflies are connected with the onset of good fortune whilst the appearance of a yellow butterfly is seen to indicate that sickness or hardship may follow.
One rather gruesome belief followed that the first butterfly seen each year should be killed in order to ensure that the next year would be full of positive change and good fortune.