Name of the first iPhone

I've gotten two answers and I'm really tired of searching for the true answer so, I came here and I would hope to think the one I get here is right: now, what is the official name of the first iPhone that came out of apple in 2007? Was it just the iPhone? was is called the iPhone 2G? I've never heard it called the iPhone 2G until like a week ago and I've gotten half and half answers from a biased and non-biased question. Never mind that though, just answer the question. PLeAsE