Man history majors are so great because they know all this stuff but they have The One Subject and once you find out what a given history buff’s Subject is you will never be bored again because they will tell you all about it with the enthusiasm of a child on Christmas morning
This is also more widely applicable.
For example: my roommate is a linguistics major. Her One True Subject is conlangs, and she can (and has) talked for multiple hours without slowing down. She’s gonna make a language and we’re going to run around yelling at each other in it, it’ll be fun.