The Kalenjin Sub tribes has eight (8) age sets revolving around 100 year cycle. Each age set span over a period of 13 years before moving to the next age set. The age sets are as detailed below.
1)Maina - 1800 A.D. - 1885A.D
2)Nyongi - 1885 A.D.- 1900 A.D
3)Chumiot - 1900 A.D .- 1924A.D
4)Saweiyiek - 1924A.D. - 1940 A.D
5) Korongoro - 1940A.D .-1966 A.D
6) Kipkoimet - 1966A.D .-1976A.D
7) Kaplelach - 1976A.D .- 1996 A.D
8) Kipnyiige - 1996A.D .- todate.
Tugen lost an age set called Maina, after they were exterminated in a war. they had traveled all the way to Laikipia and found the Masais had gone to war at Tanzania. they took all the cows and while at Naivasha, they decided to feast. incidentally, the Masais' arrived and tracked their stolen cows and caught up with them unawares around the present Naivasha and killed all the raiders. The Maina age group was therefore skipped to the next, hence, Keiyos are behind, while the Tugens are a head.
