Editing Darius the Great (section)

===Economy===
{{see also|Achaemenid coinage}}
[[File:Daric coin of the Achaemenid Empire (Darius I to Xerxes II).jpg|thumb|right|Gold [[Persian daric|daric]], minted at [[Sardis]]]]

Darius introduced a new universal currency, the [[Persian daric|daric]], sometime before 500 BCE.{{sfn|Shahbazi|1994|pp=41–50}} Darius used the coinage system as a transnational currency to regulate trade and commerce throughout his empire. The Daric was also recognized beyond the borders of the empire, in places such as Celtic Central Europe and Eastern Europe. There were two types of darics, a gold daric and a silver daric. Only the king could mint gold darics. Important generals and satraps minted silver darics, the latter usually to recruit Greek mercenaries in [[Anatolia]]. The daric was a major boost to international trade. Trade goods such as textiles, carpets, tools and [[metalworking|metal objects]] began to travel throughout Asia, Europe and Africa. To further improve trade, Darius built the [[Royal Road]], a postal system and Phoenician-based commercial shipping.

The daric also improved government revenues as the introduction of the daric made it easier to collect new taxes on land, livestock and marketplaces. This led to the registration of land which was measured and then taxed. The increased government revenues helped maintain and improve existing infrastructure and helped fund [[irrigation]] projects in dry lands. This new tax system also led to the formation of state banking and the creation of banking firms. One of the most famous banking firms was [[Murashu and Sons|Murashu Sons]], based in the Babylonian city of [[Nippur]].{{sfn|Farrokh|2007|p=65}} These banking firms provided loans and credit to clients.{{sfn|Farrokh|2007|pp=65–66}}

In an effort to further improve trade, Darius built canals, underground [[Traditional water sources of Persian antiquity|waterways]] and a powerful navy.{{sfn|Shahbazi|1994|pp=41–50}} According to Herodotus, qanat irrigation technology was introduced to Egypt, which is supported by the historian [[Albert T. Olmstead]].<ref>{{Cite book |last=Olmstead |first=A. T. |url=https://isac.uchicago.edu/sites/default/files/uploads/shared/docs/history_persian_empire.pdf |title=History of the Persian Empire |publisher=[[The University of Chicago Press]] |year=1948 |isbn=0-226-62777-2 |pages=224 |language=en-US}}</ref> He further improved and expanded the network of roads and [[Angarium|way stations]] throughout the empire, so that there was a system of travel authorization for the King, satraps and other high officials, which entitled the traveller to draw provisions at daily stopping places.{{sfn|Konecky|2008|p=86}}{{sfn|Shahbazi|1994|pp=41–50}}