Vikings/Strategy

The Vikings are primarily an offensive civilization with strong infantry and an effective navy.

Strengths
Their infantry have increased hit points which aids in pitched battles. Their unique unit is the Berserk, a powerful infantry unit with a high attack and hit point with the ability to regenerate lost hit points, slowly, over time. Berserks are good at destroying buildings and can combat other melee units effectively. Since they regenerate, they can survive prolonged combat without the need of Monks supporting them. However, even with this regeneration, Berserks are still vulnerable to ranged units and other units that possess a large attack. The Vikings also have a strong navy, having a naval unique unit, the Longboat. Longboats fire volleys of arrows and are capable of defeating any naval unit with the exception of the Korean Turtle Ship and the Saracen Galleon. In addition, their docks are cheaper to build and their ships are cheaper to create. The Vikings also get Wheelbarrow and Hand Cart for free, boosting their mid-game economy for different strategies. One last thing to note is that the Vikings' defence is surprisingly good with Fortified Wall, Architecture, Hoardings and Heated Shot.

Weaknesses
The Vikings lack many important Monastery technologies like Sanctity, have limited light and heavy cavalry (they lack Hussars, Paladins and lots of cavalry upgrades such as Bloodlines, Husbandry and Plate Barding Armor), have no Halberdiers (though the extra HP for pikeman cover this to some extent), no gunpowder units or Towers (except Cannon Galleon and Elite Cannon Galleon), no Siege Onagers, and no Fire Ships (but the Longboat can more than make up for this).

Their Berserk aren't always reliable in terms of melee combat. While they can slowly regenerate their extremely high hit points, other unique units that are not weak to melee can eventually overrun them, such as Cataphracts with Logistica.

Strategy
Viking are one of the most, if not the most, powerful civilization on water maps. Their dock bonus and the discount for all their warships allows for them to take control of the sea earlier than other civilizations. Vikings are perfectly capable to perform sea rushes in maps like archipelago and islands with their cheaper galleys from the feudal age. Despite the fact that their discount bonus was modified in " The forgotten", they can still do this. Their longboats are perfectly capable to take down almost all kinds of ships in a unit vs unit combat, but they perform better if massed since these unique vessels can be created very quickly and each one shoots multiple arrows.

On land Viking players must focus on their infantry, and are able to perform infantry rushes from the feudal age. Normally a Viking player will go for an Infantry Flush (feudal rush) on maps that have no seas or water. The extra hp for their infantry improves this tactic but other than that, it will be a standard rush. Sadly, Vikings are a lot less versatile on land than on water but if managed well they can thrive in non water maps, and should always try a rushing tactic in the early game. They get Wheelbarrow and Hand Cart for free, slightly boosting their middle game economy. While the Vikings have one of the worst cavalry in game due to lacking key important technologies (Bloodlines, Husbandry, Paladin, Hussars and Plate Barding Armor), the Vikings can still pull off a viable (but suboptimal when compared to Huns, Berbers, and Mongols) Knight rush in the game thanks to their strong economic bonuses, meaning the Vikings can pump out Knights much sooner and in higher numbers thanks to the Wheelbarrow and Hand Cart free upgrades.

Vikings are probably at their strongest in the castle age once they get berserkers and longboats. Berserkers can heal themselves slowly, allowing a Viking player to not create supporting monks in batttle. Berserkers must be paired with other infantry units at this point,  and also have some range support from siege units and archers. Gathering Infantry units in rams for a siege is also a viable tactic for the Vikings. Viking infantry units are also able to become cannon fodder as they can take a lot of damage before dying.

Strategy changes in The Forgotten
Berserkers are more useful in this expansion. Chieftains gives an attack bonus against cavalry, making them a powerful counter-unit, Berserkergang now costs 850 food and 400 gold (from 500 food and 850 gold), making this improvement cheaper than in The Conquerors. Their base HP and their training time are also improved.

Their naval bonuses (cheaper ships and cheaper dock) was changed too, but in this case reduced those bonuses; the cost bonus for their ships is now staggered and the team bonus for the dock was reduced to 15%. However the cost for the Longboat was reduced to 90 wood 40 gold ( from 100 wood 50 gold).

Strategy Changes in The African Kingdoms
As there were introduced 2 new ships, Vikings get a distinctive advantage from these new introductions as they can spam the Demolition raft for a lower cost than other Civilizations since Feudal age ( they lack the Fire Galley). The cost of their longboats in the other hand is restored to their original cost but no longer requires a castle to access them.

Chieftains Technology cost was reduced significantly, additionally the bonus against cavalry has been raised from +4 to +5.

Alliances
Vikings make perfect allies on water maps. Their cheaper Dock bonus helps them and their allies control the waterways sooner than the enemy team early in the game. Their Longboats and other cheaper ships are invaluable on any water map. Their tougher infantry also is a great for keeping control on land.

Vikings should be paired with other strong navy civilizations on water maps, such as Koreans, Japanese, Persians and Saracens. The Japanese team bonus (+2 line of sight for galleys) also helps the Viking early game water rush and scouting.

On land maps, Goths are a perfect teammate as they provide +20% faster barracks and Huskarls to counter enemy archers.

Italian Condottieri have more hitpoints for the Viking player. They can take care of enemy gunpowder units, which are dangerous to Viking infantry and ships. The strong Italian navy and archers make a good synergy with the Viking army.

Southeast Asian allies also mitigate Viking players' miseries by providing Battle Elephants and Bombard Cannons: the former as meatshields against missile fire and the latter as late-game multipurpose firepower support.

Furthermore, the Burmese offer quality monks, well-teched infantry, equally competent cavalry and Battle Elephants, enhanced by Manipur Cavalry and Howdah respectively, to cover almost all Viking players' common weaknesses, while Khmer allies grant Viking Scorpions adequate range boost to augment their anti-navy and anti-personnel firepower, not only helping them out with Hand Cannoneers.

A Vietnamese ally also grant the Vikings extra bag of tricks: gold subsidy from Paper Money provide them decent bankroll for extra berserks and longboats; Imperial Skirmisher upgrade gifts them another wise choice against enemy archers and horse archers alike; Rattan Archers, Battle Elephants with Chatras upgrade, plus equally hardy archer units to deliver fierce siege support under missile fire, not to mention their frushes also benefits from the Vietnamese team bonus if researched Cartography. Hence both "Big-Vs" can form a deadly rush trio with a Portuguese ally as well.

A Malay ally is also welcome for the Vikings, particularly in watery maps. Not only the far-sighted docks the Malay gift them to build up vigilant, fast-response garrison fleets, cheap, tanky, Heresy-reinforced Malay Battle Elephants can also screen their infantry and foot archers as mounted supplement. In return, Malay players can build up their own coastal defence network in bargain price. Even in land maps, land units of both civs can also work in harmony: Viking foot-archers, Berserks or other fully-teched Viking infantry with Chieftains upgrade bog down enemy personnel, while Malay battle elephants deliver charge against enemy siege units, allowing the mass of Karambit Warriors and sword infantry (particularly in rams) to swarm the enemy base with bulldozing effect.