Credo is an academic alternative to Wikipedia. It includes a topic pages with mind maps (examples: Velazquez or Spain) and specialized entries from several encyclopedias, dictionaries, and other reference sources (example: Representing Europe's Crisis of the Seventeenth Century in World History Encyclopedia, and Velázquez, Diego Rodríguez de Silva (1599 - 1660) in The Thames & Hudson Dictionary of Art & Artists).
The databases featured in this box are particularly useful for this class. You can learn more about databases on the Research Hub.
Try some of these subject headings in WorldCat:
Painting, Spanish 17th century | Art and society | Velázquez, Diego 1599-1660 | Portrait painting, Renaissance | Philip IV, King of Spain, 1605-1665 Art patronage | Painting, Baroque | Catholic church | Museo del Prado