You might want to look at this question I ask a long while ago before I devoted myself to a larger study of French history.

Hi, this question for English is one of the most popular questions in this sub. Here's one version from the FAQ that has some good examples, but a search will turn up many more if you're curious

• https://www.reddit.com/r/AskHistorians/comments/25c3t1/what_is_the_furthest_year_i_can_go_back_in_time/

Edit: here's a comment on French as well

• https://www.reddit.com/r/AskHistorians/comments/133ji9/so_weve_heard_the_question_asked_many_times_about/c70od8i