Sid Meier's Civilization VI: Byzantium & Gaul Pack

Summary pulled directly from Steam - Some text may only be applicable to Steam platform

This new content pack introduces Basil II as the leader of Byzantium and Ambiorix as the leader of Gaul. The Byzantine Empire can subjugate enemies with religious and military might, supported by their two unique units, the Dromon Ship and the Tagma. The Gallic horde focuses on military flexibility boosted by a backbone of culture and production with their unique Oppidum district.

Civilization VI is required to play add-on content and some features of the New Frontier Pass require the Civilization VI Expansion Bundle to work.

Includes the Byzantine Empire with Basil II, the Dromon Ship and the Tagma unique units, and the Hippodrome unique district.

Civ Unique Ability: The “Taxis” ability gives units additional Combat Strength or Religious Strength for each Holy City converted to Byzantium's Religion. Byzantium's Religion spreads when an enemy unit is defeated. Cities with Holy Sites earn bonus Great Prophet points.
Leader Unique Ability: Basil’s “Porphyrogénnētos” ability allows Heavy and Light Cavalry units to do full damage against cities following the same religion as Byzantium. Basil gains the Tagma unique unit when the Divine Right civic is discovered.
Unique Units: Byzantium features two unique units.
The Dromon replaces the Quadrireme, has additional range, and receives additional Combat Strength against units.
The Tagma replaces the Knight and grants nearby land units additional Combat Strength or Religious Strength.
Unique District: The Hippodrome replaces the Entertainment Complex district, is cheaper to build, and provides additional Amenities. Grants a Heavy Cavalry unit when the Hippodrome and its buildings are constructed.

Also includes the Gaul civilization with Ambiorix, the Gaesatae unique unit, and the Oppidum unique district.

Civ Unique Ability: The “Hallstatt Culture” ability allows Mines to provide a minor adjacency bonus for all districts, Culture Bomb unowned territory, and grant additional Culture. Specialty districts cannot be built next to the City Center and do not receive adjacency from other districts.
Leader Unique Ability: With the “King of the Eburones” ability, Ambiorix’s civilization gains additional Culture based on unit cost when a non-civilian is trained. Melee, anti-cavalry, and ranged units receive bonus Combat Strength for every adjacent combat unit.
Unique Unit: The Gaesatae replaces the Warrior. It is more expensive to train, but receives additional Combat Strength when fighting stronger units and district defenses.
Unique District: The Oppidum is cheaper and available earlier than the Industrial Zone and unlocks the Apprenticeship technology when constructed. It is defensible, offering its own ranged attack, and receives a major adjacency bonus from Quarries and strategic resources.

New “Dramatic Ages” Game Mode (Requires the Civilization VI Expansion Bundle to play)

An optional, specialized game mode with exclusive rule changes:
A New “Normal”: Civilizations always enter a Dark Age or a Golden Age in every new era, both of which are more potent than ever and eliminate Normal Ages.
New Policies: Players gain access to special Social Policies instead of making Dedications, including new and updated Golden Policies and Dark Policies that offer more flexibility and power.
New Golden Age Boosts: Entering a Golden Age with extra Era Score will increase citizens’ Loyalty pressure on nearby civs.
New Dark Age Challenges: The chaos of Dark Ages can cause cities to rebel!
New Era Scores: Players gain Era Score by completing Technologies or Civics and promoting units through combat. (Players can still earn Era Score from Historic Moments as well.)

New World Wonders

Biosphere. Increases Appeal from all Marsh and Rainforest tiles. In the Gathering Storm expansion, it boosts Power and Tourism. In other rulesets, it grants bonus Science for every Marsh, Rainforest, or Woods in the city that built it
Statue of Zeus. Gives free military units to the city that controls it and increases Production towards anti-cavalry units.

New Map Script

The Highlands map is a large region dominated by hills and mountain ranges.