Britons/Strategy

The Britons are primarily an archer oriented civilization, with many of their civilization bonuses aiding their offensive capabilities. They actually play quite good even defensivily.

Strengths
Their archers gain bonus range in the Castle and Imperial Age and are trained faster. In addition their unique technology increases their range even more and grants towers additional attack. In total their foot archers gain +3 range, giving them an advantage against the archers of other civilizations. Their unique unit, the Longbowman, has the longest range of any archer. Due to their range Longbowmen can cut down opposing forces before they can even get close. Even enemy archers will likely be killed before they get in range. If in a large enough group they are almost impossible to counter. Cavalry are the main threat of Longbowmen, but the Britons have full infantry technology so can build Halberdiers to provide close combat protection from cavalry for the Longbowmen. If played in conjunction with the Saracens, their team bonus will allow longbowmen to deal additional damage to buildings. Britons have almost full university technologies.

Weaknesses
However the Britons have several weaknesses. They have mediocre cavalry, lacking both the Hussar and Paladin upgrades, cannot build Camels, and lack Bloodlines. Their siege weapons are similarly lacking, missing the Siege Ram, Siege Onager, and Bombard Cannon, and being unable to research redemption would mean that they cannot convert any enemy siege units for themselves, therefore being greatly disadvantaged when facing enemies with bombard cannons. They are missing the Parthian Tactics and Thumb Ring upgrades, though their inherent archer bonuses compensates for this. They are also the only Old World civilization to be missing the Cannon Galleon (unless in the Forgotten expansion, where the cannon galleon is added for the Britons). This was a critical weakness in maps where water is common as this causes naval invasions to be much more difficult (nevertheless they have full dock technology tree missing only the elite cannon galleon upgrade in the Age of Empires II: HD). Before the introduction of the cannon galleon, if an opponent builds a large amount of towers near a shore a naval attack was almost impossible. This was historically quite incorrect since England was some of the first to introduce gunpowder-doted galleons and had a very powerful Navy during all the Middle Ages.

In addition, they also lack Hand Cannoneers and Bombard Cannons, thus further limiting their archer and siege options. This is also historically incorrect, as the British were known for their heavy use of gunpowder as means of expanding their empire in the New World.

Strategy
Britons should avoid Dark Age rushing (drushing) at all costs. It is critically important to frequently scout the base of the enemy to try to determine which strategy they are using. If the player sees a Barracks going up in the earlier half of the Dark Age, it is highly likely they will drush. In this is the case a Briton player must, wall themself in with palisades and buildings. It's all right to constrict the space, and try to keep the enemy out. Britons must age up on 22 population, and get an Archery Range as soon as possible. A few Archers should be more than enough to break the siege from behind the walls, and then the Britons can go out and harass  their opponent with Archers.

If a Briton player doesn´t get drushed, they should still use essentially the same tactic. Going age up on 22 population (21 villagers+a scout) and rush the opponent with Archers in the Feudal Age. Since Archers only take Wood and Gold, they shouldn't hinder their progress to the Castle age much, so long as they get a few extra Villagers on wood and gold. Britons can get out of the Dark Age faster than many other civilizations, since their Shepherds work faster. It is important to press this advantage by Feudal Age rushing (flushing) the foe with Archers as early as possible. In the Castle Age,  the Britons must upgrade the Archers who are ideally already raiding the opponent into Crossbowmen, and research as many relevant Blacksmith technologies as possible. A good Briton player must be sure to protect their Archers with Pikemen, as Knights can be hazardous otherwise.

Britons can optionally switch into Longbows in the Castle Age, but Crossbows and Arbalests are generally more effective, unless that extra one range is really important. Trebuchets make good Imperial Age back-up, as Britons lack proper Siege. The Britons must always keep some Melee units on hand (usually Champions and Halberdiers, as their cavalry is too weak to be reliable due to the lack of Bloodlines and missing important cavalry upgrades), as enemy units will often hide in rams to approach safely to the archer lines.

Defensively, their long ranged archers play well. Also, Longbowmen behind Fortified Walls or inside a Castle, accompanied by a Trebuchet with Warwolf researched, is an easy, cheap and effective option. If micromanaged properly, Longbowmen can take down Bombard Cannons and Onagers, and British Trebuchets have an advantage over every other Trebuchet, except from maybe the Japanese and Hunnic ones. Their only weakness in defense is the absence of strong gunpowder unit to take down group of units quickly or Rams, though their Halberdiers, Champions, and their Longbowmen. The Yeomen technology is also helpful for defense, as towers increase their attack damage.

The Britons will have a hard time with some civilizations such as the Goths, due to Huskarls being a powerful anti-archer unit with a high pierce armor, and the Malians due to the extra pierce armor for Champions and Halberdiers. Cavalry civilizations such as the Huns, Mongols, Magyars, Persians, and the Berbers are also a big threat to their fragile Longbowmen and archers, which is why it's important to back the Longbowmen up with Halberdiers. The Britons make a great civilization against civilizations like the Aztecs who miss cavalry.

Strategy changes in The Forgotten
Yeomen was moved from Imperial age to Castle age, allowing Britons to strike with archers heavily earlier than in The Conquerors (now with +2 range at Castle age and +3 range in Imperial age). New Tech Warwolf allows Trebuchet to do blast damage (damaging enemy buildings and units near to the firing point) so a combined force of archers, longbowmen and Trebuchets makes the Britons even better in a siege in this expansion. In addition, they have the ability to build Cannon Galleons. Warwolf and cannon galleon are critical changes since they eliminate the two main weaknesses of Britons before the expansion (absence of a more powerful siege weapon and a siege ship). Thanks to this, they have become a good naval force since they have full technology apart from elite cannon galleon (but no civilization bonuses that make their navy dangerous).

Alliances
Britons in team games are great at supporting their team mates, as their long range archers can aid allies from long distances, even when besieging an opponent or when defending a location.

Their team bonus greatly benefits any civ that have buffs for the archery range units, as this will help to produce Arbalests, Skirmishers, Hand Canoneers, Cavalry archers and the Inca Slinger faster. If played in conjunction with Berbers this will also apply to the Genitour.

If played in conjunction with the Magyars, their Longbowmen can have a Line of Sight as high as 15, the highest of any unit in the game, with the exception of several gunpowder and siege units. Also, the Saracen Team bonus is a great addition to the Britons, as this lets groups of Arbalests or Longbowmen act like a siege engine that outranges Castles and Towers.

Southeast Asian civilizations, introduced in Rise of the Rajas, have also proven to be more than capable allies of the Britons, as they provide Battle Elephants as viable meatshields and an alternative of Paladins, together with Bombard Cannons as gunpowder component and late-game fire support they need, allowing their Longbowmen to return fire against hostile Monks and missile units. Apart from that, the Burmese strong infantry and cavalry rosters also provide them decent cavalry cover as makeshift defence against cavalry-oriented civs, plus allowing Briton players to train Monks and snatch relics quickly. The team bonus of the Malay also provide costal defence boost for the revitalized Briton navy. Khmer players contribute range boost for Heavy Scorpions, grant the Briton players lethal, "friendly-fire free" alternatives against monks, foot archers and slower infantry, in exchange for the ability of earlier archer rush.

In comparison to other Southeast Asian Civs, nonetheless, only the Vietnamese have win-win synergy with the Britons: they can reveal locations of the enemy bases at the beginning, allowing Briton players to conduct surgical raids or rushes effectively, particularly archer rushes; their unique Paper Money technology grant decent gold subsidy for extra Longbowmen, foot archers or Trebuchets; their Battle Elephants, strengthened by Chatras and Bloodlines, plus equally resilient Rattan Archers, prove capable of safeguarding Briton Longbowmen from missile fire, allowing longbow contigents to deliver long range snipes against hostile Monks; and, last but not least, their team bonus allow the Britons to amass Imperial Skirmisher rapidly as their own late-game measure to counter archer-oriented civs, or to dominate the Trash Wars.