Is this a bug or an Easter egg (or Christmas gift)? In my last game up 'til well into the medieval era I seemed to get extra (i.e. "gifted" or free) techs. For example, I was actually researching Rifling, and when it popped I also got another tech -- Dynamite, I think. It wasn't caused by a completed RA. The only thing different in this game was that I managed to build the Magellan's Voyage wonder which is supposed to give you a discount on techs already discovered by other civs; does it give you those techs free instead??