A lot of people (myself included) sometimes find it hard to trade with the AI fairly. When you find yourself a whole bunch of techs behind some think the only answer is to fight a war and get techs for giving the AI peace, or to just give up the game. This is not always true. Maps, Right of Passage (ROP), and luxuries can be a powerful trading tool if you are in the right position.
On this game on Regent Level, and had two continents to myself and had just been contacted by Persia (they settled a city on my continent) and I found I was several techs behind. I only had a map of my territory, because I hadn't done any sea exploration. Here is how I caught up in tech:
