In the centuries following its creation, a painting is often subjected to changes, either in appearance or its physical location. While some paintings led a quite steady life, being passed down from family member to family member, others were transported from country to country, or even from continent to continent. They were given away, bequeathed, sold, auctioned off, stolen or even confiscated. Being in the hands of different owners, the appearance of a painting was often changed. They were reframed, adjusted in size, restored or (partly) painted over. Aside from alterations made by people, paintings are also subjected to the natural aging process. Varnish darkens over time, paint layers sometimes become more translucent, colors can fade or change due to chemical reactions of the pigments and craquelure becomes more distinct.
Archival sources such as inventories and publications such as auction catalogues have been helpful in retracing the whereabouts of a painting. Not only these written sources, but also images such as reproduction prints and old photographs, and any physical evidence a painting might hold, occasionally provide information about what has happened to a painting in the past, from its creation until the present day.