0 A.D.

0 A.D. is a historical real-time strategy open source game, published by Wildfire Games. It focuses on the years between 500 BCE and 500 CE. 0 A.D. will be released in two parts: the first part will cover the 500 BCE–1 BCE period; the second part will span 1 CE to 500 CE.

The game aims to be entirely free and open source. In addition, the developers do not get paid for their work, nor will they charge for their product. It has been in development since 2000, with actual work on the game starting in 2003.

The game's source code and binaries are released under the GPL General Public Library version 2, with the artwork licensed under Creative Commons Attribution-Share Alike 3.0. Various other included utilities are released under the BSD, ISC, MIT and Zlib libraries where appropriate. Version 0.0.1.5 is currently available via the Ubuntu software archives.

History
0 A.D. was originally a mod concept for Age of Empires II: The Age of Kings. With limited design capabilities, the team soon turned to trying to create a full independent game based on their initial ideas.

In November 2008 developers confirmed releasing of the project as open source soon. On July 10, 2009, Wildfire Games released source code for 0 A.D. under the GPL 2, and made the art content available under the CC-BY-SA.

On April 2, 2010, Wildfire Games announced the release of a pre-alpha version of 0 A.D., on May 16, 2010 they released the second and on July 11, 2010 the third pre-alpha.

On August 16, 2010 Wildfire Games released a first alpha version entitled "Alpha 1 Argonaut".

Game content
The game is about economic development and warfare. The 0 A.D. team aims to deliver an experience that is refreshingly innovative but at the same time familiar, focusing mostly on the military aspect of real-time strategy. The game will pursue a strong sense of historical accuracy without damaging gameplay. It also aims for a high degree of replay ability by being easily moddable and the formation of a large online community. The player will have to build a city and an army following the rules of standard real-time strategy games, collecting resources and constructing buildings. The game will include multiple units and buildings specific to each civilization. It will include both land and naval units.

Civilizations

 * Carthaginians: will have the strongest navy in the game; the fiercest contenders on the high seas. They were also masters of naval trade, extending their trade routes even beyond the pillars of Hercules and circumnavigating Africa. They deployed towered War Elephants on the battlefield to fearsome effect.
 * Celts: The Britons and Gauls are the antithesis of the rigid organization of Rome. A fierce horde of woad-painted Celtic warriors charging across the plains was a fearsome sight. They considered the bow and other ranged arms to be a weapon of cowards, and excel in hand-to-hand combat. Not known for their machines of war, they have minimal navy and siege. They construct mostly wooden buildings, which are fast and inexpensive to construct, though far less robust than their stone counterparts.
 * Hellenes: Controlling the representatives from the Hellenic region, the player has the power of Sparta, Athens and Macedonia at his command. As the forebears of philosophy, democracy, geometry, and Hellenistic art and architecture, they are considered to be civic minded. However, do not discount the strength of their stone structures, the resolve of a Hoplite in phalanx formation, or their historic ability to steal victory against seemingly insurmountable odds.
 * Iberians: The Iberians were fathers of the art of guerrilla warfare, capable of lightning strikes against an opponent and withdrawing before he can mass an offensive. Their foot units are some of the fastest and most rapid-firing in the game, particularly their Balearic Slingers. A number of their ranged units also have the unique ability to fire flaming missiles. Toledo steel grants them superior metal weaponry.
 * Persians: The Persian Empire is the most cosmopolitan civilization, levying a wide variety of troops from their vassal satrapies. Their infantry are weak and poorly-equipped, little more than cannon fodder, but can be massed in vast numbers. They have the strongest (though most expensive) cavalry in the game, and are the only civilization that features all forms of cavalry, including the fearsome cavalry archer. Their cavalry is equally exotic, including camelry, mahout elephants, and scythed chariots. They are known for their lavish wealth, grand architecture and strong trade empire through the Silk Road.
 * Romans: The great conquering imperial powerhouse that swept across Europe, the western shores of the Mediterranean and North Africa in its early days as a Republic. The Romans are notable for their regimented military, powerful siege engines, broad range of naval vessels, politics, and ability to adapt.

In future expansion packs, the developers hope to expand the number of available cultures by incorporating additional civilizations from 1 AD to 500 AD. The list will not be finalized until the first edition has gone gold, but possible civilizations include Imperial Rome, the Germanic tribes (including Vandals, Saxons, Goths), Sarmatians, Late Rome, Eastern Rome, Parthians, Huns, Dacians, Indians, Egyptians, Vikings.

Buildings
Each civilizations buildings will look unique, as well as be in their native language.


 * The Civic Center is the fundamental core structure of a town or city, and controls all principal functions of a civilization. From here, the player is given the ability to train the essential economic and basic military units that are crucial to their nation’s survival, especially in the early developmental stages of their city. The civic center can also be used as a gather point for nearby resources if a resource center isn’t in the player's budget. In province-based game styles, construction of civic centers will be necessary for claiming new territory. Similar to Ensemble Studios' Age of Mythology, Civic Centers will have to be built over a Settlement, limiting the number of Civic Centers that can be on a map.


 * Houses are quintessential elements to the growth of the player's town, granting them additional living space for their citizens and soldiers. Each house the player constructs contributes additional space to their overall population limit, and each unit built will fill a space in this population cap. Essentially, the more houses one has, the larger one's army can be, and the easier it will be to defeat enemies.


 * A mill will extend the gathering radius for mining stone and metal and chopping wood. The player then be able to salvage nearby resources that are too far from their civic center to be gathered from. They’ll also be able to improve mining and chopping-related abilities by purchasing upgrades.


 * Farmsteads allow extended gathering radius of food sources, such as wild animals herds or nearby crops. Much like the mill, they will allow the player to reach previously unattainable resources that are farther away from the center of their city, and provide a number of upgraded tools for their villagers to improve their gathering rate. Also, fields must be constructed within range of farmsteads or the civic center to be used.


 * By garrisoning animals in a corral, each animal will provide a steady trickle of food to the player's supply, or the player can slaughter an animal for a quick burst of food in more desperate situations. Garrisoning horses, camels, or elephants in a corral will reduce the production cost of units that use the animal.


 * Docks can only be constructed on the edge of a body of water, and provide all naval related services, from trading to fishing to the construction of naval war machines. Depending on the surrounding landscape and location of enemies, docks can often be central structure of the player's nation’s economic and diplomatic survival. If water-based transportation is required to reach enemy territory, it is crucial that docks be protected.


 * Markets serve a number of economically related purposes, primarily consisting of bartering resources between cities and allied factions. Merchants travel back and forth between markets to exchange resources for a steady profit. Only one market can be constructed per city or territory, so location is key in order to generate the fastest income.


 * Walls are essential to the protection of the city, and will keep enemies at bay while the player constructs defending forces. Gates can be constructed on longer segments of walls to allow passage of one's soldiers in and out of the city without compromising security. Many players find that walls can become an essential aspect of an overall defensive strategy while slowly amassing an impressive city and keeping the enemy at bay, then eventually ‘booming’ with indomitable forces.


 * Scout and guard towers can be used to provide an additional radius of sight to look out for approaching enemies, and can be upgraded to provide ranged fire to prevent enemies from entering city limits, or to keep enemies at bay while defensive forces are prepared.


 * The Military Center, or Barracks, is where the player will train the bulk of their military forces. Military technologies are also researched here in order increase the stats (attack, armour, speed, health) of one's soldiers. Two barracks can be built per territory.


 * In addition to providing the ability to train religious units, the Temple will provide a source of healing for any wounded civilians or soldiers that stand within its vicinity. Temples are not essential elements of the player's architectural conglomerate, but can be helpful if the civilization been damaged by the tides of war.


 * Fortresses are where most of the game's factions train their super units, heroes, and siege weapons (there is one notable exception). Strong, but expensive, Fortresses have ample room for a large garrison and is easily defended. One of these may be built per territory.


 * Special Buildings are structures unique to each faction and have some kind of unique function. This image shows the Hellenic (Greek) "Tholos" Special Building, which trains Hellenic heroes, and the Persian "Kakh" (Palace) Special Building that grants the Persian player a large economic bonus.

Reception
0 A.D. was voted one of the Top 100 Best Mods and Indies of 2008 by ModDB. For 2009, 0 A.D made it in the Top 100 Best Mods and Indies as well as winning third place for Player's Choice Upcoming Indie Game of the Year.