Eras of the State
In Gapla, a state gets an period named after them if they are currently the most influential state. Once a state is no longer the most influential, the state's period will pass. A group of periods is an era. Here is a table showing the periods and eras of Gapla.
https://drive.google.com/open?id=1sBKtFZsaqnroT6AsZWruvxQSKZZZuC3alr9O9pazx40
https://drive.google.com/open?id=1sBKtFZsaqnroT6AsZWruvxQSKZZZuC3alr9O9pazx40