Primary sources include original texts, maps, documents, objects, etc. They are the original source of information, as opposed to a later work that builds on it, such as an analysis, report or description. Look for leads in the research literature. For example, if an article/book cites a primary work, see if you can track this down.
This page provides a few primary sources that may be useful.
Both of these sites have millions of digitized and downloadable historical books and other documents – often, you can search the FULL TEXT of these sources!
