What is the difference between a journal written by an eyewitness to an event and a play written about the same event

A journal will be everything from that persons view of everything that person had seen. a play is edited for entertaiment purposes

The difference is whether it is a primary or secondary source. Because the journal was written by an eyewitness it would be a primary source. However, because the play was only based off an event and contains no firsthand material in it, it is a secondary source.

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