Gaul is a versatile civilization that has bonuses when it comes to culture and production. We're going to overview the Civilization, learn its strengths and how to play it throughout the game. This guide is focused on the Gathering Storm expansion (Byzantium & Gaul pack).
To win Civilization VI as Gaul you can either go the domination route from the beginning or turtle yourself to get a cultural victory. Either way build a lot of Oppidums (Industrial Zone replacement), plan your cities and districts accordingly to Gaul's rules (differs from other civilizations) and start the game settling cities as fast as you can because you will need all the space you can get.
Gaul is an expansive civilization that has to quickly gain territory in order to have enough space for its cities. The civilization excels at generating Culture and Production.
Mines gain +1 Culture, grant a +0.5 adjacency bonus for districts and trigger a Culture bomb when built, claiming surrounding unowned tiles. Specialty districts do not receive adjacency bonuses from other districts and cannot be built next to the City Center.
"Come, enemy. Send an ambassador, for I have something to say which will benefit us both"
Receive Culture equal to 20% of the Production cost after training a non-civilian unit. Melee, ranged and anti-cavalry units receive +2 Combat Strength for each adjacent military unit, including enemy units.
Gaul's unique district, it replaces the Industrial Zone. The Oppidum behaves like an Encampment in the sense that it acquires Outer Defenses and Ranged Strike along with the city once Walls has been built.
Cannot be built next to City center (same as any Gaul district)
To sum it up, this is what you shouldn't do (don't be like me):
Notice the Oppidum (looks like an Encampment) in between two Aqueducts, you should never do that when playing Gaul.
This is what you should do instead:
The Oppidum is adjacent to two quarries, this is not perfect, but a decent layout as the district receives +4 Production adjacency bonus. Strategic resources instead of Quarries are also good.
Galic unique melee unit. It replaces the Warrior. While the Gaesatae has the same base Combat Strength as the Warrior, it receives a +10 bonus against units with higher base Combat Strength and it also receives a +5 bonus when fighting against District defenses. However, the Gaesatae has a higher production cost (60 vs 40) than the unit it replaces and it also cannot be upgraded to Swordsman, its next upgrade is Musketman.
60 or 120 or 240
Musketman (370 and 20 cost)
The Gaesatae will allow for combat against units from civs that are more advanced in the tech tree, the +10 Strength bonus will be specially good against Spearmen and Heavy Carriots. Before starting making Gaesatae you should consider using the Agoge Policy card as the unit's production cost is higher than its replacement.
Gaul has a bias towards copper, diamonds, iron, jade, mercury, salt and silver.
Gaul's best type of victories are Domination and Cultural.
Domination is one of the most suitable paths for Gaul. Ambiorix's leader ability helps a lot because the combat bonus per unit surrounded yours applies for both ally and enemy units. Gaul's unique unit replaces the Warrior, so you will have an advantage starting the game, but remember, the Gaesatae has a higher production cost, so don't start spamming them, instead use the Agoge policy card first or make sure of having cities with production. In comparison to other Domination civilizations such as Gran Colombia or Byzantium, Gaul doesn't hit as hard, but it makes it up producing more units and advancing in the civics tree while doing so.
Science victory is indirectly good while playing as Gaul, while the civilization doesn't have science bonus, it does have a pretty high production, thus being able to get many Eurekas. The rapid expansion of cities should also indirectly help with science, although remember leaving some space in between your city-centers and mountains, as specialty district cannot be constructed to city center.
Having bonus culture from mines and producing units Gaul has a good quickstart in the civis tree and throughout the game. The fact that the civilization has a very high production also helps a lot while compéting for wonders or simply constructing Theater Squares. Gaul has an easy time defending against warmongering civilization while not having a big army, Oppidums act as an Encampment if the city has Walls, which in turns increases your tourism output in later eras.
Ignore religion, the civilization has zero religious bonuses and it is also harder to place Holy Sites correctly because of not being able to construct specialty districts adjacent to city-center. Gaul is one of the best civilizations when it comes to ignoring Holy Sites.
Gaul has a 'better than most' ability for diplomatic victories, higher production helps a lot while competing for wonders such as the Statue of Liberty and Mahabodhi Temple
Militaristic civilization? Go with the Sanguine Pact. Gaul doesn't have any other options anyways, Owls of Minerva would be a very far second place, only thanks to the society's early bonus (+1 Economic Policy slot). Vampires and Vampire Castles will help throughout the entire game.
Reach the Medieval Era
Grants a Vampire unit in your capital, and allows your Vampires to construct Vampire Castles (maximum two per empire).
Reach the Industrial Era
Grants a Vampires unit in your capital. Increases maximum Vampire Castle build to three. Your vampires now intimidate adjacent enemy units, reducing their combat strength by 5. Pillaging now costs Vampires 1 movement.
Reach the Atomic Era
Grants a Vampire unit in your capital. Increase maximum Vampire Castle builds to four. Units can teleport between Vampire Castles.
Best starting build is something like Scout>Slinger>Builder>Settler. You need to rush the Mining technology because mines grants culture and +1 Culture is very important early game
Gaul needs to expand faster than other civilizations because its cities cannot have specialty districts adjacent to them, and therefore require more space. On the governors side, rush Magnus with the Provision promotion. On the civics side rush Early Empire to start pushing out settlers. Deity AI will get mad and probably attack you, but the Gaesatae and extra production will help you to win those battles.
Science: Have 1 decent Campus early game
Gaesatae's big advantage is that it can fight and win against more advanced units, also Oppidums can be constructed much earlier than Industrial Zones, but this doesn't mean you should completely ignore science early game, instead you should look for a good spot to build a Campus there. In my case, at a point in the game, I had 5 cities, 3 Oppidums and 1 Campus.
The Civilization VI developer's team don't want us to be comfortable with districts, the latest civilizations released have very different ways of district layouts. Gaul is not the exception, specialty districts cannot be placed next to the city-center, this makes it so you have to plan a bit more while settling new cities.
Early game you should build a Campus and a lot of Oppidums. Later in the game you should build accordingly to the victory path of your choice.
Disregard Holy Sites, acquire Oppidums.
Constructing at least 1 good Campus (3+ adjacency bonus) early game is enough to not fall behind in science (higher difficulties). However, remember to plan your Campuses accordingly to the city-center restriction.
Encampments are important, but you don't really need them early in the game. Prioritize Oppidums.
Yes, Oppidums look like Encampments in the strategy view. Symply the most important district for Gaul. Build a lot, don't place them next to Aqueducts as you would with regular Industrial Zones. Place them adjacent to Strategic Resources and Quarries.
Gaul is hard to play against, dealing with both Oppidums and Encampments is very difficult, even more so when the October 2020 patch arrives, because the AI will promptly rebuild walls.