Oromo society was traditionally arranged in accordance with gadaa, a social stratification method partially based on an eight-year cycle of age sets; yet over the centuries the age sets grew out-of-alignment with the actual ages of their members, and some time in the 1800s another age set system was established.
Under gadaa, every eight years the Oromo would hold a popular gathering called the Gumi Gayo, at which laws were established for the following eight years.
A democratically elected leader, the Abba Gada, will be in charge of over the system for an eight-year term. Gadaa is no longer in wide practice but remains significant.
Keywords: gadaa, Gumi Gayo, Abba Gada,