I think you should talk with them honestly. It's important to explain them that you should do in your life what you want. Tell them that you are sure you won't break your life. There is a few ways to change their mind. First, show them how much you like history. You should also improve them that you are very good in this subject. Try to gain the best notes in school. In my opinion their will favour you in your plans when they notice there is no problem with employment after archeology. Your parents should get to know that that's your passion. Of course, if it's true.