An example of this, from http://www.hepguru.com/monalisa/introduction.html, for the Mona Lisa by Leonardo da Vinci is
Acquired by François I, either directly from Leonardo da Vinci, during his stay in France, or upon his death from his heirs, the painting remained in the royal collections from the beginning of the sixteenth century to the creation of the Central Arts Museum at the Louvre in 1793. We know that it was kept at Versailles under the reign of Louis XIV and that it was in the Tuileries during the First Empire. Since the Restoration, the Mona Lisa has always remained in the Louvre Museum, a key piece of the national collections.
How does this relate to genealogists and family historians? Genealogists look at both original and derivative sources and the provenance shows which of these it is. Original sources are always preferable, but depending how how and by whom a record became a derivative source changes how much trust you would have in it (for example, a microfilm of a church record by the FHC would be considered more trustworthy evidence than a transcription of the same record by an unknown person).
Additionally, there are many items that genealogists own items that we received from others, such as family bibles, letters and diaries or artifacts like jewelry or china. Where did these come from and how did you get them? This can be particularly important for an item such as a bible which will give birth, death and marriage dates of ancestors. Was it passed down in the family from the original owner? Was it found on a site such as eBay? How do you know who wrote the names and dates in it?
This information can and should be included in your source for the item. If you are citing a family bible, after the source for the item itself you would include a sentence such as "The Jane Smith Family Bible was passed to her daughter Sue Smith Jones, to her granddaughter Jean Jones White, to her niece Amanda Perrine."
For further information, please consult Evidence Explained by Elizabeth Shown Mills.