How to read boring stuff?

So I'm in a history class right now, and the professor assigns like 100+ pages per week of reading. I have no issue reading actual books, but when it comes to reading history books, my speed drops drastically. All semester I've been dropping like, 8 hours a week trying to cover my reading for this class even skimming the pages, but its so hard to focus on because it's just so boring. I need to read about 50 pages today, but I find my focus shifting constantly trying to get this in. Any advice for reading stuff that's basically just blocks of info?