Editing Science and technology (section)

==Currency==
:{{Main|Currency}}

For currency, coins are the manner used most frequently, especially by merchants, owners of establishments, and the noble classes. [[Smallfolk]] might use either coins or barter. 

Thus far, no society in [[Westeros]] or [[Essos]] has been described as using paper currency. Most societies use currency in the form of coins made from precious metals such as gold, silver, or copper (with a few notable exceptions, such as the iron coins used in [[Braavos]]). Contracts written on parchment or paper are also accepted, though these are not "currency" as such: for example, the [[Brotherhood without Banners]] during the [[War of the Five Kings]] would give commoners notes promising to pay them for supplies they took after the war ended.{{ref|asos|39}} Similarly, [[Tyrion Lannister]] drew up contracts promising to pay the [[Second Sons]] with gold from [[Casterly Rock]] in return for their aid in restoring him to his lordship of it.{{Ref|aDwD|66}}

A notable exception on this system is the system of the [[Dothraki]], a nomadic people from [[Essos]]. The Dothraki are commonly said to neither buy nor sell.{{ref|ADWD|2}}{{Ref|ADWD|71}} It is considered to be unmanly.{{Ref|TWOIAF|Beyond the Free Cities: The Grasslands}} Despite the common saying that Dothraki do not sell,{{Ref|ADWD|5}}{{Ref|ADWD|50}} the Dothraki do sell their captives on occasion to the [[Slaver Cities]].{{Ref|ACOK|12}} They call these slaves "gifts", and in return receive gifts from the slavers.{{Ref|ADWD|50}} Giving and receiving gifts is the common way of Dothraki for doing trade.{{Ref|ADWD|5}}{{Ref|ADWD|50}}{{Ref|ADWD|71}} However, giving a gift in return might not always occur immediately upon receiving a gift.{{Ref|ADWD|36}} Common trade is allowed in the sacred Dothraki city [[Vaes Dothrak]], where, by the leave of the ''[[dosh khaleen]]'', merchants and traders gather to exchange goods and gold.{{Ref|TWOIAF|Beyond the Free Cities: The Grasslands}} There, they mostly trade with each other, and little with the Dothraki themselves.{{Ref|agot|54}}

[[George R. R. Martin]] has compared the Westerosi coinage to medieval coinage, saying that ''"Westerosi coinage is probably more complex than actual British medieval coinage"'', despite some similarities.<ref>[[So Spake Martin]]: [http://www.westeros.org/Citadel/SSM/Entry/1243 Blackwood-Bracken Feud and Coinage (August 13, 2003)]</ref>