An important piece of information often included on labels is the acquisition information, or how the artwork got to the museum's collection. This may include an accession number (such as SC 1879:1) and the credit line, which will share a bit about how the museum got the artwork—for example, if the museum bought the artwork or received it as a donation, exchange, or transfer.
Let's look at accession number for Thomas Eakins's In Grandmother's Time, for an example. The "SC" means it belongs to Smith College. The "1879" means it was bought in the year 1879. And the "1" means it was the first painting bought that year.