Historical event - something that happened before the present (i.e. in the past).

Chronology - the science that deals with measuring time by regular divisions and that assigns to events their proper dates.

Cause - something that brings about an effect or result.

Effect - something that follows a cause or antecedent.

Artifact - an object showing human workmanship or modification.

Document - a writing that conveys information.

Primary source - a piece of evidence (document or object) that dates back to the time when an event occurred.

Secondary source - evidence, descriptions, or explanations that shed light on past events but are not directly connected to those events or date back to the time when an event occurred.

Historical account - a description or explanation of something that happened in the past.

Theme - a subject or topic.

Region - an area with one or more common characteristics or features, which give it a measure of homogeneity and make it different from surrounding areas.

Change over time - to become different with the passage of time.

Evidence - something that furnishes or suggests proof.

Point of view - a position from which something is considered or evaluated.