If you want to write for history you need to troll history periodicals, journals, and universities for a gig. Folks will give you a start similar to !@#$%! but you need a portfolio to vouch for your quality and expertise. You can use your college papers but you're going to need to revise them significantly so they don't come across simply as "college term papers" but they will be a "better than nothing" start. Cut the down and edit them to look like articles, essays, or blurbs. Remember though, historians are a scholarly bunch so the education is highly competitive, essentially Masters Degrees or go home. See A LOT of professors, instructors, and other university types like to make their hustle on the side free-lancing or writing part time. It boosts their own clout in their field and their resume and university folks don't make nearly as much money as the astronomical costs of tuition may suggest.
You can also expand your field to political analysis but this tends to be a crowded market for free-lancing..
Most people with history degrees become teachers or research librarians, the pay is more consistent.