If you look carefully at this button, you can see decoration in the form of a bird with three young.
The design, a pelican pecking at its breast to release blood to save its young, is a symbol within Christianity for Christ who sacrifices himself on the cross for Man’s sins. The motif first appeared in the second century AD in the Greek text Physiologus in which stories about a number of animals are recounted with Christian symbolic meaning.
The button was found with other undecorated buttons in a wooden box, which in turn was found in a barrel on the ship’s lower gundeck. The pelican motif also appears as part of a decorative shield which was found on Vasa’s sterncastle.