Dramatic Ages is a game mode introduced with the Byzantium & Gaul Pack (DLC) from the New Frontier Pass.

Its premise is simple: every era of a civilization is either a golden age or a dark age. (Only the first age is normal).

What's dramatic about this mode is that in a dark age you will lose a percentage of your cities. At the hardest level, deity, you will lose 25% of your cites! What's worse is now free cities also exert loyalty pressure, potentially flipping neighbours like dominoes.

But fret not. To help with era scoring in Dramatic Ages, you also get +1 era score for every technology, civic and unit promotion.

Some planning at game setup can help.

If you play a map script in which you can pick natural wonders, make sure to choose Lysefjord, especially if you're playing a water map or a naval civ.

It grants your naval units that pass by a promotion giving you easy era score.

In the main campaign (i.e. without Dramatic Ages) expanding early is tantamount.

However in Dramatic Ages you may want to hold out on doing that. In the first era it's pointless rushing settlers if you slip into a dark age. Your investment in settlers will be in vain when your cities instantly fall into free states.

So explore. Let your capital grow (instead of building settlers). Build infrastructure for science and culture. Take the time to construct a wonder or two. This will grant you era score helping your push into a golden age.

As your empire expands build infrastructure in your core cities. (i.e. the top 75% which have full loyalty).

If you go dark in the first era, prior to settling any other cities, guess what? You don't lose any cities. And what's more, the threshold for a golden age in the next era is lower, making a golden age an easy target to achieve.

This strategy is difficult for ancient civs like Babylon and The Maori. Their unique units and infrastructure unlock early on making an early golden age a given. However for classical and later civs it may be easier to aim for an early dark age.

Failing which, in preparation for your first dark age (which is inevitable) settle cities which can easily be taken back. For example if you have a large navy, then settle coastal cities so that you may easily recapture any that fall in a dark age.

Sometimes in an era you maybe on a roll overshooting the golden age target.

Please stop exploring, building wonders, promoting units or doing anything that grants era score (other than research and culture).

Tip: save unit promotions. This will help reduce the golden age threshold for the next era and allow you to effectively rollover era score.

The objective is to have as many golden ages as possible and at all costs avoid a later dark age. That is the trick to surviving Dramatic Ages.

Instead of building walls and encampments in frontier cities, mostly you want to churn out units there. Because in the event the city becomes free you don't want to have to go up against the walls you built yourself.

Originally posted by Kurdish proverb (from Civ 4):

Do not throw the arrow which will return against you

If and when your cities do fall, you will have ensured there were no walls there, aiding your recapture of them.

You also get era score for returning cities to your empire lost in a dark age.

Originally posted by Civilopedia:

The rules for earning Era Score are adjusted, encouraging players to engage in conflict

As the Civilopedia suggests, Dramatic Ages encourages war, especially in the late game.

You get +1 era score for every unit promotion (past your first), so fielding a large army and warring will grant plenty of promotions and era score helping the late game push into golden ages.

It's safe to say you can ignore grievances and warmonger. (It's preferable to have poor diplomatic relations instead of losing up to 25% of your empire to a dark age!)

You get +5 era score for eliminating a civ, which in the later eras may be essential for a push into a golden age.

Also the fewer civs there are the less competition for world wonders and the more time you will have for each world era.

That is also why Dramatic Ages mode is easier on smaller map sizes (or more specifically when playing against fewer opponents).

The only place I recommend ever building walls is in your capital. That is the one city that can never fall into a free state in a dark age.

I also recommend building an encampment in your capital.

Build the wonder the Terracotta Army.

It will give all your units a promotion which in Dramatic Ages mode grants +1 era score for each promoted unit you own!

So plan ahead by building an encampment next to a flat green tile on which to place the wonder. Also you can delay building this until a later era when you may find it difficult to accrue era score for the next golden age.

Some civs really do shine in Dramatic Ages mode.

Try Mali, Phoenicia, Australia, The Mapuche, The Maya, Babylon, Byzantium, Gaul, China, France, England, Egypt, The Inca, Gran Colombia, Kongo & Vietnam.

Also Tokugawa.

The diplomatic civs like Canada, America and Sweden fare less well.