Although little is known of the prehistory of the peoples currently inhabiting Kenya, it is believed that the land has been more or less continuously inhabited since the birth of mankind - about 4.5 million years ago, as the numerous fossil finds around the edges of Lake Turkana, up in the far north of the country, elegantly testify. These discoveries of early hominids have earned Lake Turkana the title, 'The Cradle of Mankind', although still older finds were subsequently made in Ethiopia, to the north.

Within a multiplicity of tribes constituting around 45, the main distinctions that have been made by anthropologists, and to a lesser extent by Kenyans themselves, are based on broad ethno-linguistic classifications, which use the existence of common root languages as a basis of defining cultural (and racial) differences and similarities between peoples.

The logic is simple in theory, if not in practice: in the same way that Europeans make a distinction between Romance, Celtic, Latin, Nordic and Slavic tongues, and thus peoples, so it is in Kenya that distinctions are made between Bantu, Cushitic and Nilotic-speaking peoples. The cattle-herding Nilotes occupy the plains of the Rift Valley in the west of the country, which cuts across the whole of Kenya from north to south; the camel-rearing Cushites live in the desertic northeast; and the agricultural Bantu are in the more fertile highlands of central and southern Kenya, as well as in a few highland areas near Lake Victoria.

The Swahili, who are sometimes also classed as a distinct ethno-linguistic group, occupy the coast. The arrival of each of these groups can be sequentially dated, although ascribing precise dates to particular migrations and tribes is difficult if not impossible. It should be borne in mind that these classifications, and the names that are used, are almost entirely academic, and moreover were coined by European scholars rather than by Kenyans themselves. Periodic disputes arise among researchers as to the precise meaning of the classifications, and many alternative labels crop up

The Cushites
Of the major ethno-linguistic groups, the first to arrive in Kenya were the Cushites, the first of whom (ancestors of the present-day Somali, Rendille and Wa-Boni) are believed to have entered north and northeastern Kenya around 2000-1000BC from Ethiopia. Some sources quote a figure of 9000BC for this, although it appears to confuse them with the hunter-gatherers. Needless to say, there's little evidence linking any particular ethno-linguistic group to any archaeological finds dating from that time.

Many subsequent migrations have since occurred, the latest in the mid-1900s, so that tracing the ancestry of any of these peoples is a confusing and probably pointless exercise. Cushitic-speaking peoples in Kenya include the Borana, Burji, Gabbra, Orma, Rendille and Somali

The Nilotes
The next major linguistic group to arrive were the Nilotes who, as their name suggests, originally came from the Nile Valley, probably in Southern Sudan. The first of these peoples are believed to have arrived around 500BC, although Nilotic migrations only became substantial some five hundred years ago, with the arrival of the Luo and Maasai.

Their main direction of movement was southwards along the plains of the Rift Valley, which favoured both their cattle-raising lifestyle, as well as their rapid, all-conquering advance into the country. By the seventeenth and eighteenth-centuries, they had reached Tanzania, where their advance was finally stopped. Nilotes who have kept to their nomadic way of life, namely the Maasai, Turkana, Rendille and some sections of the Pokot, nowadays consider themselves as oppressed, dominated and discriminated against by the state and by the more numerous agriculturalists.

Nilotic-speaking peoples in Kenya include the agricultural Luo (14% of the population, and Kenya's second-largest tribe), various tribes who came together in the last century to form the Kalenjin (Kenya's fourth-largest, at 11%), the Maasai (1.5% of the national population), the Pokot, Samburu and Turkana

The Bantu
The last major group to arrive (excluding the numerically-small but all-powerful Europeans in the nineteenth-century), were the Bantu-speakers, the first of whom probably arrived some two thousand years ago. Bantu-speaking peoples in Kenya include three of Kenya's five largest tribes, namely the Kikuyu (largest, with 21% of the national population), the Luhya (third largest at 13%), and the Kamba (fourth or fifth largest, with around 11% of the population).

Other Kenyan Bantu include the Chuka, Embu & Mbeere, Gusii, Kuria, Makonde, Meru, Mijikenda and the Taita (these links are the same as those accessed from either the pull-down list or the interactive map).

The Swahili
The mostly Muslim Swahili-speaking people on the coast are sometimes classed as a separate ethno-linguistic group, although their history and ethnicity is much more complex than that of the groups mentioned above, and involves many recent migrations and influences from as far away as the Arabian Peninsula and the Indian Sub-continent, as well as influxes from Bantu and Cushites.

The thing that distinguishes the Swahili (which in Kenya includes the Shirazi and Bajuni peoples) is their long period of contact with other cultures, notably through commerce with Arabs, Persians, Indians and even Chinese. Contact with Europeans began in 1498, with the arrival of Vasco da Gama en route to India, but European influence was minimal until the period of British colonisation.

The first cities and towns are believed to have developed quickly along the Kenyan coast in the first few centuries AD, of which Lamu, Malindi and Mombasa survive to the present-day. Some sources even mention Roman settlements, though these were almost certainly Phoenician. The long period of contact with both Arabs and Persians from Shiraz, especially between the eighth and thirteenth-centuries, led to the early diffusion of Islam among the Swahili (and indeed, the word Swahili is believed to derive from the Arabic term for coast, Sahel).

The Swahili language - Kiswahili - developed primarily from a mixture of Arabic and local Bantu languages, though it also included elements of Persian, Portuguese, Hindi, and English. It is now Kenya's official language, spoken as a second language by the majority of Kenyans (their first language is generally that of their tribe).