When you're learning about a new topic, sometimes you just need some basic background information. Reference works (encyclopedias, dictionaries, almanacs, atlases, etc.) provide facts and basic information about people, places, movements, events, particular pieces of art, or whatever it is you want to learn more about. Wikipedia is an example of a reference work.
There are specific reference works that focus on topics in Art History. Many of these sources are available online via the library's website, and some are in print in the library.
Reference works usually aren't suitable for citing in your paper, but they can give you a good place to start when you need to know foundational information about your topic.
Formerly Grove Art Online, it includes the entire 34 volumes of The Dictionary of Art, with articles as well as links to images on gallery and museum web pages around the world. Includes biographies of artists and searchable images.
Offers fully-indexed, cross-searchable dictionary, language reference, and subject reference works published by Oxford University Press, including Oxford Companions Series. Covers a wide range of fields and includes illustrations, maps, timelines, biographies, and links to authoritative websites.