Museum sites are great places to find background information on your artist or movement.
Do a web search, but look for museum names in the url.
Examples: moma.org, tate.org, metmuesuem.org, nga.gov
Knowing more about your topic in a general way will help you think of good keywords for your search.
Note: ARTstor is NOT included in OneSearch (The catalog and most of our other databases are.)