The Exchange Treaty of 9211 was initially signed by New Delta, Teolos, Brocenback and Alkhan and was later directly ratified by Tirkvah and Siquan. The City of Sands ratified it via the J’harderith because the residents needed to negotiate import and export prices. The only city state to never ratify the treaty was Gruck, which never really needed to. The treaty determined the human language, renamed Common, as the official business and diplomatic language and set up a standard currency, calendar and measurements.
The standard unit of Hominian currency is the Credit, a purely electronic currency that can be exchanged physically by currency cards issued by various banks. Keep in mind the credit is really several different currencies going by the official designations New Delta Credit, Teolian Credit and Brocenback Credit. This is just like the dollar, which is used in several countries but isn’t the same currency. For example, the US Dollar and Canadian Dollar are not the same thing despite both being dollars. Each city-state manages the credits as they are used in the city-state itself. Therefore, the credit has several different exchange rates, one for each city-state. The reason is due to each city-state’s vast differing economy. Trying to secure a single exchange rate between New Delta and Tirkvah or even Brocenback and Alkhan without causing a collapse is impossible.
The advantage to the credit is that because it’s purely electronic, exchange is instantaneous and automatic. This means your money is good anywhere credits are accepted, no hoop-jumping required.
Terrall is a planet orbiting a star called Alpha Solaris. It has a moon called Umbra and three sister planets called Rognark, Grognark and Shognark. This is important because Hominia uses the elven solar calendar which I based on Earth’s solar calendar for ease of use. There are 365 days in a year, divided into twelve months of 28, 30 or 31 days, with a leap year every four years adding an 29th day to the second month. The current novellas and Sandworm Rodeo take place in the year 10021. The year zero was the date of the first elven records, the start of recorded history.
Note that I don’t give names to months or even have weeks. There are three reasons: First, I found making up month and days of week names would just be tacky, especially since I’m using our calendar as a base. Second, in Terrall there is no concept of a week because there are no weekends. As weekends are based on real-world religious traditions, they do not apply in Terrall. Unless you take days off on the weekend, weekdays become meaningless anyway (and I’m speaking for personal experience) Third, when drafting the exchange Treaty, nobody could agree on what names of the months would be. Instead, they just ditched them.
So when somebody wants to express a specific date within the same year, they say the month and day. For example, “Would you like go out with me on 4/3?” 4/3 is pronounced like it looks: “Four three.” When expressing a day within the same century, they’ll say “What were you doing 8/12/19?” pronounced “eight twelve nineteen.” Outside of the century they’ll just say the full date: “On 6/12/9982.”
When stating relative days, things we week use weeks for, people on Hominia just state the numbers of days ahead or behind you’re referring. “What are you doing next week?” becomes “What are you doing in about five days?”
In the real world, most of the world uses the metric system except the United States. I’m a United States resident. Therefore, in order to keep measurements straight in my own head, Hominia used the imperial system: feet. miles, pounds, ounces, quarts and gallons. Temperature is measured in Fahrenheit. In universe, this was, again, the elven system.
Rest of the world:
Orcs and trolls on Elemchi, while not part of the Exchange treaty, have adopted a similar calendar and measurement systems. They, however, use a hard currency because constant warfare can knock out electricity. Uthirans on Uthira have no use for measurements or currency and live so long that calendars are pointless.