noun
historical fact
A fact established by historical evidence; used in academic, journalistic, and everyday contexts.
この小説は歴史的事実に基づいている。
This novel is based on historical facts.
史実 is a more concise, formal term for 'historical fact', often used in academic writing, while 歴史的事実 is slightly more explanatory and common in general contexts.
Compound of 歴史的 (historical) + 事実 (fact).