You can either pretend to be them or write about them. But, for example, if you were asked to write about the celts and you started with "The celts...." you would lose all marks. If it was someone like Christopher columbus and you started with either "Christopher Columbus..." or "I am Christopher Columbus....." Then you would be fine. Its confusing but thats how they mark
It Depends , for example if you're writing a P.I.H on a factory worker in the industrial revolution you may need to pretend you're
him/her and for any known people eg . Columbus you will write about them .
Hope this helped & Good Luck !