They appeared as a distinct group around the 16th century after their settlement on the slopes of Mount Kenya. They are the largest group of Bantu speaking people, and number over 2,500,000. Mythology simplifies what history complicates, when the legend says that the founder of the tribe was named "Gikuyu". God (Ngai) commanded Gikuyu to build a homestead. God not only gave him land but also a wife "Mumbi". Gikuyu and Mumbi became the ancestors of all the Kikuyu. She bore nine daughters, and those were the progenitors of the nine clans: Achera, Agachiku, Airimu, Ambui, Angare, Anjiru, Antui, Millizig;t. Aitlierandu. During the 19th century the Kikuyu suffered constant raids from the Galla and Somali. To protect themselves they had to join force with the Maasai and the Athi (another Bantu group).
Eventually the Athi were absorbed by the Kikuyu in 1870 during the inter Maasai wars, and many Maasai took shelter in Kikuyu land. Those political refugees stayed there, married there and now a good half of the Nyeri district is of Maasai origin. Jomo Kenyatta the most famous of the Kikuyu, himself had a Maasai grand-mother. But still conflict between the two tribes did occur. There existed a sort of no man's land between the Kikuyu living around Mount Kenya and the Maasai in the Rift Valley. On their arrival the Europeans took advantage of the space and settled themselves there.
They became politically involved very early and in 1920 they formed the "Kikuyu Association". The association took care of the Kikuyu needs and complaints against the colonial system. They were also deeply involved in the Mau-Mau uprising until independence when Jomo Kenyatta became the first president of Kenya. Today there are over 400,000 Kikuyu in Nairobi who are prosperous businessmen or traders, but most of the others live in the traditional crop growing way. They cultivate maize, millet and beans. Like the Nilotes, cattle means wealth and they also have an age-set system. The young boys become warriors after the circumcision.
Then 15 years later they reach the status of elders and sit at the "kiona", the elder council, where all political decisions are taken. The basic unit of the Kikuyu organization is the family or "Nyomba". Each individual is a member of a nyomba, as well as [tie member of a larger unit, the clan or moherega.