Unique units related to a golden age

In a golden age of an empire it is most likely to have developed a unique unit that distinguished them from others. Each civilisation must not have one special unique unit. But each civilisation gets a unique unit after a golden age is triggered.
The unique unit that is rewarded depends upon the latest obtained military related technology. The reward depends upon the treats of the leader and the current state of your empire

Some leaders will be able to choose between some abilities of the unique units (creative, philosophical), others are more likely to create a certain kind of unit: i.e. aggressive for attacking, religious for defence; organized are more likely to have larger armies, financial lower support cost; industrial needs a lower production time.
The type of the unique unit is more dependent on the current state of the empire and its needs.
In a golden age the army is able to adapt some properties that are useful in that time.
The computer needs to evaluate the resources that are available, the diplomatic relations at the continent and also far away, and determines which type of properties the unique unit will get:

War: extra strength/offence
Tense borders: extra defence
Enemy is far away: extra mobility/horse unit
On an island: naval unit
Rough terrain: treat that terrain as it were plains or combat
bonuses on that terrain
Poorly developed country: faster worker/ Specialized in a few types of improvements
Current resources in the empire:
no horses:fast other unit
no iron:unit which requires no iron but is almost as strong as the otherno oil:an artillery on horse unit which replaces tank or give you a modern unit on coal, hydrogen or nuclear powered
no uranium:a hydrogen bomb

In this case it will be more useful to start a golden age, if you lack a strategic resource you will find a way to adapt during the golden age, which is a large advantage for smaller countries with fewer resources. There are many unique units and it is thus possible that the Mongols end up with a legionnaire and the Romans with a Panzer tank.

A country may only trigger a few golden ages, maximum of 1 every 250 turns, so it will be vital to trigger the golden age at the best time to create the unique unit you want. If you are researching iron working you might want to wait until you have completed your research. So you are able to build a strong swordsman or you can create a similar unit without iron.

After the golden age ends after 10 turn, the unique unit will still be available until it is replaced by a modern unit. An empire is thus maximal capable of triggering 3 golden ages, the cost of triggering a golden ages grows exponentially: golden age 1: 2GP, golden age 2: 4 GP, Golden age 3: 8 GP. Most civilisations will only trigger 2 golden ages, because they lack the GP in the first 100 turns or they simply want to wait with triggering the golden age until some new discoveries are made enabling new units, such as swordsman, horseman, knights, infantry, tanks, modern armours, helicopters or nukes.

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