Civilization V Tech Tree

Technologies and their quotes from Sid Meier's Civilization V (Dates are taken from Civlopedia if available. Otherwise, reason is stated in parentheses) Note: This is not a science. The technologies are very general, so it's hard to pin specific dates down. I've tried to isolate the different eras to reflect Civ's tech tree but this comes at the expense of some historical accuracy, especially around the Renaissance.