Try Author and Subject searches for prominent people, organizations (e.g. specific monastic orders), movements (e.g. Reformation)
Remember to try different regional terms, broader and more specific (e.g. Europe, France, Paris), also different era terms (19th century, 600-1500)
These keywords are Library of Congress Subject Heading vocabulary indicating primary sources:
sources, letters, interviews, speeches, personal narratives, diaries,
correspondence, sermons, notebooks, sketches, description and travel,
treaties, pamphlets, biography (includes memoirs), newspapers,
periodicals, pictorial works, art, architecture, portraits, caricatures
and cartoons, cookery, decorative arts, furniture, material culture,
guide books, maps, fiction, poetry, periodicals, newspapers,
bibliography, early works to 1800
Try a Subject Search for: