Corsairs' Stronghold was added to game in July 2013. It has been (prolly) the most played battleground since. It was originally available to characters level 30 and higher. Although all characters were equalized to level 60 stats, they had only skills and glyphs they had learned. Later battleground was restricted to level 65 characters only. Battleground has always used equalized gear.
Corsair's Stronghold has two rounds. Team has to defend the fortress and the Anchorstone (also called Crystal) inside and attack in other round. Team must generally break outer and inner gate to attack enemy Anchorstone, but sneak attack by climbing the ladders or airship landing with small team may succeed.
First round has time limit. Limit is extended when capping middle pyre or breaking the gates to maximum of 15 minutes per round. Second round has same time limit as first one. It might be bad idea to give your opponent more time to finish objectives.
Dead players will respawn in 10 seconds. Player may select to spawn in starting camp or any of the captured pyres. Capturing pyres will give new spawn places. There are three pyres to capture, one close to each of outer gates and one on ramparts middle. Capturing middle pyre gives easy access to attack inner gate.
There are several tanks and siege weapons available. Two tanks near both outer gates should always move to cover outer gate from bombardment from middle sieges. Middle sieges can attack players near both outer gates, inner gates and everyone near middle pyre.
There are few movable tanks on outer ramparts that can be moved to defend or attack middle pyre, or shoot defenders on inner ramparts. Furthermore there are two sieges inside inner gate in Anchorstone chamber that can defend broken gate, or can be captured to attack Anchorstone itself.
All tanks and sieges can also shoot attackers using airships to drop to inner yard or directly to inner rampart. Sieges do fixed 16 000 damage to players, but have good change to knock down anyone hit.
Battleground awards Bellicarium credits and reputation. There's also Vanguard mission that gives gold, xp, item xp, Skill Advancement xp, Vanguard credits, Dragon Scale and various PVP gear materials on victory. January 2019 PVP Disciplinary/Harmonic/Impregnable gear can be, and should be enchanted to +6 using materials from CS.
Winning or losing a match also affects the character’s personal rating. Characters on top of rating get shiny titles at end of the season.
There are several achievement related to battleground. Characters who have won 150 matches get the "Black Pearl" mount.