Eras: Important, but poorly documented?

[Doomheit]

1. Is there any way to determine the specific era of an opposing civilization? You can get a general idea from the buildings/style of their cities, but even my spies can't tell me if someone is classical/renaissance or atomic/modern.

2. Does advancing in eras require the a civic from that eras, a tech from that era, either, or both?

There are tons of era-based bonuses and civilizations and buildings but its difficult to determine when they come into effect. Also, seeing as there's only a handful of eras, it's hard to "play around" with when there's hours of play between advancements.

 

[Guandao]

1. There is a bar with the little icons of the leaders' faces in the bottom of the tech tree pop-up, same with Civic tree
2. It only requires one of the two.

 

[Doomheit]

Ahh, thanks, I see it now!

Little bars and little icons strike again. At least it's not as small as the great person scroll bar that tripped so many people up...

 

[CoolLizy]

Important, but poorly documented?

Civilization VI in a nutshell.