Technologies

Civilization 4 has 86 technologies in the base game by Firaxis's own count (against 81 in Civilization 3), from Fishing at a cost of 40 to Fusion and Future Tech at 6,000 each, and Beyond the Sword adds six more: Advanced Flight, Aesthetics, Laser, Military Science, Stealth and Superconductors. Every technology unlocks something: a unit, a building, a worker action, a civic, a wonder, a trade option or, for seven of them, a religion. The game's own manual is vaguer and says "over 80", and GameSpot's guide lists 84 of them with their costs; the table at the end of this page gives all of them.

Quick facts

How research works

Research is paid for with commerce: the slider on the main screen turns a share of every city's commerce into research and the rest into gold (and, after Drama, culture), and only city commerce can become research, never gold from huts, pillage or trade missions, per the Civilization 4 manual, pp. 26 and 67. The manual's worked example: a city with 30 commerce at 80% science, a Library and one Scientist makes (24 + 3) x 1.25 = 33.75 research a turn and 6 gold (p. 157). Libraries, Monasteries, specialists and civics such as Representation and Free Religion all add to it.

Each civilization starts with two techs of its own (the Leaders page lists them), and techs also come from tribal villages, from trading with other leaders and from research (base manual, p. 65). Some come free: the Oracle grants one when it is built, the first civilization to discover Music receives a Great Artist (base manual, p. 91), the first to discover Liberalism receives a free technology (GameSpot's guide), and a Great Person can be spent to discover a tech, usually one in its own field.

Switching research costs nothing. Partial progress on a tech is kept when you change to another, though it slowly decays if left too long, per the manual, pp. 66-67. Choosing a far-off tech on the tree (F6) queues its prerequisites along the fastest path automatically.

The tree has no eras that gate it. Soren Johnson's design notes in the manual's afterword (p. 180) explain that Civilization 4 dropped Civilization 3's separate eras and added "or" prerequisites, so that "you only need Guilds OR Education to research Gunpowder", and GameSpot's 2005 review noted that "different technologies aren't tied to specific epochs anymore" (GameSpot, Oct 26, 2005). That is why two games rarely follow the same path.

Costs rise with difficulty. The manual lists costlier techs among the handicaps of higher difficulty levels (pp. 166-167), and game speed changes how many turns research takes; the costs on this page are the base values GameSpot listed for version 1.00 (see Difficulty Levels and Game Setup).

Techs that found religions

Seven technologies found a religion for the first civilization to discover them, in one of its cities: Meditation (Buddhism), Polytheism (Hinduism), Monotheism (Judaism), Theology (Christianity), Code of Laws (Confucianism), Philosophy (Taoism) and Divine Right (Islam), per the manual, pp. 81-82. Religions covers what a religion does. GameSpot's guide called Buddhism "the easiest to found on the technology tree" and advised players aiming for early religions to pick a leader who starts with Mysticism (GameSpot, Jan 18, 2006).

Key techs and what they unlock

Early techs decide what your land can do. Agriculture, Mining, Fishing, Hunting, Mysticism and The Wheel need nothing first (manual, pp. 69-71); Pottery brings the Cottage and Granary, Bronze Working lets Workers chop forests, reveals copper and enables the Slavery civic, Masonry brings quarries and the Pyramids, and Writing brings Open Borders and the Library (GameSpot's guide). Slavery and Chopping and Cottages and Specialists explain why those three matter so much.

Most Civics arrive with a technology. Monarchy brings Hereditary Rule, Code of Laws the Caste System, Feudalism Vassalage and Serfdom, Civil Service Bureaucracy, Banking Mercantilism, Liberalism Free Speech and Free Religion, Democracy Universal Suffrage and Emancipation, and Communism State Property, per GameSpot's guide; the Pyramids unlock every Government civic regardless.

Diplomacy is gated by techs too. Alphabet allows tech trading, Paper map trading, Currency gold trading, Military Tradition Defensive Pacts, and Communism or Fascism Permanent Alliances (GameSpot's guide); see Diplomacy.

Trade and movement change with Sailing (coastal trade), Astronomy (ocean trade), Currency and Corporation (+1 trade route per city each), Engineering (+1 road movement), Steam Power (Workers 50% faster) and Railroad (railroads), all as GameSpot lists them. In Beyond the Sword, railroads need access to coal or oil (Beyond the Sword manual, p. 46), and trade along rivers needs Sailing (p. 25).

Some techs end old advantages. Calendar obsoletes the Obelisk and Stonehenge, Scientific Method the Great Library and the Monastery, Steam Power the Hagia Sophia, and Fiber Optics the Kremlin in GameSpot's 1.00 table, so research also decides when a wonder stops working.

Future Tech is the last entry. GameSpot's table gives it +1 happiness and +1 commerce in all cities and a cost of 6,000; the sources read for this page do not say how many times it can be researched.

Tech trading

Trading techs needs Alphabet known by at least one of the two leaders, per the base manual (p. 102). A technology is an "immediate" trade item, so it can be swapped for other immediate items (gold, maps, other techs, peace, cities) but not for "annual" ones such as resources or gold per turn.

GameSpot's guide warned that the AI leaders "aren't swindled": they usually offer lesser techs for more advanced ones, and a military tech you give away can come back at you when that rival declares war a few turns later (GameSpot, Jan 18, 2006). The final Beyond the Sword patch, 3.19 (Jun 11, 2009), also "Fixed a bug in AI war declaration in exchange for technologies".

Choosing a tech path

No single path is best. GameSpot's guide said research choices "depend on the situation": research Masonry early when stone is near, for quarries and faster wonders; Bronze Working early to chop forests; Archery, Horseback Riding and Bronze Working for an early army; and the religious techs from a Mysticism start for a religious game (GameSpot, Jan 18, 2006). Johnson's own aim, in the manual's afterword, was a tree where different games take different paths.

Paths that players name, such as the "Oracle slingshot" or the "Liberalism race", are community terms; no official or press source read for this viki explains them, so this page does not describe them as rules; Early Game Strategy covers the openings the sources describe.

Leonard Nimoy and the tech quotes

Every new technology comes with a quotation read aloud. Leonard Nimoy narrates "at the beginning of every new game and each time you research a new technology", and GameSpot listed him among the game's good points in its Oct 26, 2005 review. The manual credits him as Narrator.

The tech tree was also sold as a poster. The Windows Gold Edition, which bundled Civilization 4 and Warlords and reached stores on Jul 17, 2007, came with a behind-the-scenes DVD and two posters, one of them the tech tree.

Changes in patches and expansions

Patch 1.61 (2006) made Horseback Riding a classical tech, gave forest chops +50% with Mathematics, moved the map-centering effect from Astronomy to Calendar and rebalanced tech prices, per the Warlords manual, p. 103, so GameSpot's 1.00 costs below are the launch values.

Beyond the Sword added six techs and moved others, per the Beyond the Sword manual, pp. 25 and 44-46:

• Aesthetics, an early tech, is now needed for Drama and Literature, for the Parthenon and for several other wonders.
• Fiber Optics needs Laser or Computers; Robotics no longer needs Plastics directly; Computers needs Plastics.
• The Laboratory needs Superconductors, the Military Academy and the Grenadier need Military Science, Cavalry also needs Rifling, and the Trireme needs Metal Casting.
• Stables go obsolete with Advanced Flight; Monuments, Obelisks and Stonehenge with Astronomy.
• Espionage opens with Writing (see Espionage), and corporations need the Corporation tech plus one more (see Corporations).

The Beyond the Sword manual does not print the new costs; it points to the in-game Civilopedia and tech tree.

All technologies (version 1.00)

Base costs, prerequisites and unlocks as GameSpot's guide lists them for the game as shipped. "A and B or C" means A plus one of B or C. Beyond the Sword's six techs and its moved prerequisites are listed in the section above.

Source: GameSpot: Civilization IV Walkthrough, Research and Technologies table, Jan 18, 2006 (its table omits Hunting and Education; two of its typos, "Wiring" and "Eduction", are corrected here). Hunting, Music's Great Artist: Civilization 4 manual, pp. 69 and 91.

Frequently asked questions

How many techs are in Civ 4? Civilization 4 has 86 technologies in the base game by Firaxis's count, and the Beyond the Sword expansion adds six: Advanced Flight, Aesthetics, Laser, Military Science, Stealth and Superconductors.

What is the first tech to research in Civ 4? Civilization 4 has no single best first tech: GameSpot's guide advises picking by the land and resources around your cities, such as Bronze Working to chop forests, Masonry near stone, or a religious tech like Meditation when your leader starts with Mysticism.

How do you trade technologies in Civ 4? In Civilization 4, one of the two leaders must know Alphabet, and then technologies can be swapped in the diplomacy screen for other immediate items such as gold, maps, other techs or cities.

What does Future Tech do in Civ 4? In Civilization 4, Future Tech costs 6,000 in the shipped game and gives +1 happiness and +1 commerce in all cities, per GameSpot's guide.

Who reads the technology quotes in Civ 4? Leonard Nimoy reads Civilization 4's technology quotes, one each time you discover a tech, and narrates the start of every game.

Which techs found religions in Civ 4? In Civilization 4, Meditation founds Buddhism, Polytheism Hinduism, Monotheism Judaism, Theology Christianity, Code of Laws Confucianism, Philosophy Taoism and Divine Right Islam, each for the first civilization to discover it.

Does switching research lose progress in Civ 4? No: Civilization 4 keeps the research already put into a tech when you switch, though the manual says that progress slowly decays if left too long.

Sources

• Sid Meier's Civilization IV manual (Steam-hosted PDF), 2K Games and Firaxis Games, 2005
• Civilization IV: Warlords manual (Steam-hosted PDF), 2K Games and Firaxis Games, 2006
• Civilization IV: Beyond the Sword manual (Steam-hosted PDF), 2K Games and Firaxis Games, 2007
• Civilization IV Walkthrough, GameSpot (Doug Radcliffe), Jan 18, 2006
• Civilization IV Review, GameSpot (Andrew Park), Oct 26, 2005
• Civilization IV: compare features (archived), 2K Games and Firaxis Games, 2005
• E3 '07: Civ IV enters Golden age, GameSpot, Jul 9, 2007
• Civilization IV: Beyond the Sword Update Released, Valve (Steam), Jun 11, 2009