The Galley is a warship available to all civs (except for Denmark, Friesland, and Scotland, which get the Longship instead). It is a short-range ship, and formerly the only warship available to combatants (except for cannon ships). Genoa can upgrade this ship to the Galleass.
Trained at: Dock
Armor/Pierce Armor: 0/6
Special: +3 vs. lancers and all ships, +2 vs. buildings. 4 bonus armor vs. anti-ship/anti-lancer units
Veteran Chivalry players will be familiar with these ships--it used to be that this was all you had, navally. Now, however, this is outclassed by the War Cog, which is faster, benefits from Blacksmith techs, and takes up one fewer pop slot (3 vs. 4). It also has too low of an attack to be much of a shore bombarder, although it does do handsomely against rams.
Galleys do, however, excel in running down Privateers, since those ships have a minimum range of 3 and Galleys can close in fairly quickly. Some civs also have production bonuses on these ships, making their production worthwhile. A player should produce War Cogs whenever possible, but don't neglect galleys.
Among the many types of ships in the world, there is none so illustrious nor long-lived as the galley, whose use continued in Western navies in spite of the appearance of more sophisticated watercraft such as tall ships well into the 19th century. Galleys were easy to build, and cheap to outfit, and, in the Mediaeval Old World, were thus suitable for naval warfare which generally involved littoral action. At the same time, the flexibility of a galley meant that the ship was also popular with pirate crews who terrorised the Mediterranean, because its shallow draught allowed it to be hidden along the small islets that dotted the Mediterranean, and its agility also allowed it to take on larger but clumsier merchant vessels. Even long after tall ships became more agile and more destructive in power, galleys continued to be used in conflicts throughout Asia, Europe and even the Americas until the height of the Industrial Age, when steam power made oar propulsion all but obsolete save for the smallest of vessels.
- Rise of Kings Wiki; Galley War Galley