Primo can be searched for eBook encyclopedia content.
Oxforld Bibliographies Online - collections of potential relevance: Art History; Atlantic History; British and Irish Literature; Literary and Critical Theory; Philosophy; Public Health; Sociology; Urban Studies; Victorian Literature
Oxford Reference Online - contains almost 200 dictionary, language reference, and subject reference works published by Oxford University Press
Encyclopedia of European social history from 1350 to 2000 (2001) print or eBook
The Atlantic World
Napoleonic Europe (1789-1815)
An encyclopaedia of Napoleon's Europe (1984) print
Twentieth-century Britain: An encyclopedia (1995) print
Kaleidoscope of Poland: A cultural encyclopedia (2015) print
Encyclopedia of Western colonialism since 1450 (2007) eBook
Jewish History & Antisemitism
Encyclopedia of Jewish history and culture online (2017) eBook
Subheadings "politics and government," "economic conditions," "social life and customs," "social conditions," and "intellectual life" can be useful in providing context for your topic.
When you have identified several primary subject headings on your topic, also search for "historiography" as a subject heading.
European history as a whole is demarked by the following dates: 1789-1900, but narrower subdivisions exist for nation-state and thematic histories. like "19th century," or "1848-1870."
When you are searching for subject headings as part of your quest for secondary sources, pay attention to subheadings like "Sources," "Maps," "Biography," "Correspondence," "Newspapers," "Personal Narratives," etc. The first of these indicates a collection of primary source types; the latter indicate specific types of primary sources.