I was looking for a quick reference on what techs triggers each era.

Example: You have entered the Modern Age.

I was looking for a quick reference on what techs triggers each era.

Example: You have entered the Modern Age.

There isnt a single tech that does it. Instead each tech is assigned an era in CIV4TechInfos.xml. So there are a bunch of techs with their era attribute set to the modern era. You (as a player) are switched to the modern era when you research any of them.

Basically if you research a tec with an era more advanced then the one you are in you are upgraded to that era.

A new age is triggered when you get your first tech in that age; it doesn't matter which one. The poster tech tree that came with the original Civ4 shows the techs in each age differently coloured, or in Anion's excellent booklet each tech is labelled with the appropriate Age.
To enter the Modern Age, for example, the trigger tech could be Flight, Refrigeration, Plastics, Radio, Rocketry or Ecology; the other Modern techs all depend upon at least one of these.

Hi

You can also see which techs trigger a different age when you look at the tech list for what to reaseach next. In the description of what the tech does like what units, ablities, what it obseletes, what other techs it leads to etc. It will also say something like "will lead to the so and so age" if it is a tech that will trigger into the next age. Which is kinda handy if you are trying to get a quest done before you get to a specific tech age and dont want to get to it too soon :)

Kaytie

i remember entering the classical and medeival eras on the same turn. happened when researching CoL (to classical) and oracle to Civil Service in OCC. i haven't done OCC in BtS. with math triggering classical and being a requirement for CS in warlords and BtS, that must have been in vanilla. sure leads to a lot of pop-ups!