What was the American republican party before Trump?

Non American and I'm early 20s so all my awareness on American politics has been the last 10 years.

But I think its important to learn so I've seen comments and posts before saying -" I'm republican but I don't believe in Trump and his laws- "so here I ask

What was the American republican party before Trump took over. I see a lot of names but I never know who they are and what they mean I really only modern politics