Detail of: Thomas Rowlandson and Auguste Charles Pugin, British
Institution (Pall Mall), 1808. Hand-coloured etching and aquatint
(26.9 x 33.5 cm). National Portrait Gallery, London: acquisition number
NPG D15343. Source: Wikipedia.
This guide is about European painters working in the fine art tradition, from the Middle Ages to the end of the eighteenth century. Many of the resources listed will also be useful for studying other media, other areas, and other time periods.
You may also want to run supplementary searches in these databases:
For introductory articles:
Some resources for women old masters: