One major difference between a theme and a period is how time affects both concepts.
Explanation:
When investigating, historians look for common ideas that kept on appearing in the past, this repeated patterns or subjects are called themes. For example, common themes in history are archeology, human rights, philosophy and politics. Themes can be found throughout different times and sometimes overlap different eras, On the other hand, a period is a distinctive and specific timeline in which one or more events occur, but a period has a specific beginning and a specific end, unlike a theme that can be found in throughout different periods.
