Originally posted by FortyJ
Until we get libraries in all of our cities and until we get to a point where we have several more cities than the other civs, we are going to have a difficult time keeping up in the tech race.
Also, we shouldn't be too quick to increase our science spending just yet. We are currently building Horsemen and will want to upgrade those units en masse to Knights as soon as that advance becomes available. We will need much gold to accomplish this.
Nonetheless, I think our Science Dept will play a very important role for the rest of the game once the Great Library loses its effectiveness. We will need to research desirable techs before the other nations do so that we can sell them at a significant gold per turn. This will not only allow us to increase our tech research rate, but also hinder the other civs' ability to keep up.
Currently, I think our best bet for such a tech would be Engineering. The AI likes to shoot for Monarchy, Republic, Feudalism, etc. If we start working towards Engineering, we may just discover it first and can therefore sell it to the others at a premium.