Civilization VI Secret Societies is a game mode that came out with the Ethiopia Pack. It introduced the concept of Secret Societies in the form of governors whose promotions give us powerful bonuses, access to new buildings, units and improvements. We will focus on The owls of minerva strategies and perks.
The Owls of Minerva are a secret group of powerful and wealthy individuals. They focus on government, trade and espionage; which in Civilization terms translates to having more Gold, Policy slots and Spies.
Promotion title
Unlocked by
Effect
Reach the Medieval Era
Allows you to construct the Gilded Vault building, a powerful replacement of the Bank.
Reach the Industrial Era
+1 Wildcard Policy slot. +2 Spy capacity. Your cities gain +4 Loyalty per turn and +1 Amenity when your Spy is in their territory.
Reach the Atomic Era
Whenever an offensive spy mission is successful, you also gain half of the Gold, Faith, Culture, and Science that the targeted city earned that turn. Earn 3% of your Gold treasury as Gold per turn (up to 1000 Gold per turn).
Having 1 extra Trade route capacity when the city has a Harbor is a powerful bonus that should not be overlooked. Civilizations with unique Commercial Hubs and Harbors such as Netherlands, Egypt, Cree, Mali, England and Phoenicia benefit a lot from this, but also Civilizations with general district bonuses such as Japan or Germany.
Extra Culture from adjacency bonus is relevant too, although this should be thought of as a culture replacement only, as having both Harbors and Commercial Hub districts in your cities will mean there is not going to be room for Theater Square districts. In this way the heavy focus in gold won't harm the advancement in the Civics tree.
The Owls of Minerva works well with Civilizations centered in spionage or that receive benefits from having Commercial hub districts. Any type of victory is achievable thanks to the powerful bonuses when it comes to spies and covert operations.
As with any other Secret Society the first Owls of Minerva promotion is a powerful one. You receive +1 Economy Policy slot, which is great for rapid expansion because it gives space for the Colonization policy (+50% production towards Settlers) and any other at the same time.
Once the Medieval Era is reached the owls of Minerva allow you to construct the Gilded Vault, which is a building that replaces the bank. To benefit from this the sooner, research should be pointed towards Banking. Make as many Commercial Hub districts and Harbors (in the same city) as you can, Gilded Vault provides 1 extra Trade Route capacity when the city has a Harbor. Sell all your Diplomatic Favor, buy Traders with it.
Make lots of spies, reach full capacity. Receiving 1 extra Wildcard policy slot and +2 Spy capacity makes it so covert operations will run smoothly. Also later in the Atomic Era you will gain Gold, Faith, Science and Culture yields when a mission is completed successfully.
Use your spies to wreak havoc around the world! Also remember that you will earn 3% (up to 1000) of your treasury as gold per turn, this means if you manage to save 33k gold you will receive 1k for free every turn. 33k while having an army of spies is easily achievable.
The French led by Catherine de Medici (Black Queen) receive bonuses when it comes to covert operations. Catherine's Flying Squadron grants 1 extra Spy when Castles is researched and also all Spies start as Agents with a free promotion.
This might not seem like much, since the Owls of minerva spy bonuses hit later in the game, but having them started with 1 level of promotion will make it so you have spies fully promoted sooner than usual. The sheer amount of covert operations are going to be enough to grant you gold, science and securing the victory.
The english people led by either Victoria or Eleanor of Aquitaine will have excellent synergy with the Owls of Minerva. The Royal Navy Dockyard has a much lower production cost than what it replaces, the Harbor. Having this district and Commercial Hubs together is easier for the english, and therefore you will make better use of the Gilded Vault, which provides 1 extra Trading route capacity when the city has a Harbor (or equivalent).
The Cree benefit from extra trading routes thanks to Poundmaker's leader ability, Favorable Terms: Trade routes grant 1 extra food in the sending city and 1 extra gold in the destination city per camp or pasture at the destination city. Having extra trade route capacity works really well for the Cree.
Phoenicia Harbors are replaced by Cothon, which has a lower production cost and boosts the productions of Settlers and Naval units.
Japan districts receive extra adjacency bonuses, this means having Commercial hubs and harbor is already beneficial without the Owls of minerva, but then also having the Gilded Vault culture bonus (that depends on Commercial hub adjacency bonus) and having extra trading routes will make it so Japan has very good synergy with the secret society.
Mali is one of the civilizations that synergices best with the Owls of Minerva. Having the Suguba (Commercial hub replacement, cheaper), extra gold yields from international trade routes and the ability to purchase Commercial Hub buildings with Faith make it so the Malian people are simply too good when working with the Owls of Minerva.