According to tradition, the original followers of the present Dlamini clan of the Swazi country migrated south before the 16th century to what is now Mozambique. Following a series of conflicts with people living in the area of modern Maputo, the Ngwane, as they then called themselves, settled in northern Zululand in about 1750. Unable to match growing Zulu strength, the Ngwane moved the center of their kingdom northward in the 1810s and 1820s. Under King Sobhuza I they established themselves in the heartland of modern Swaziland, conquering and incorporating many long-established independent chiefdoms, whose descendants also make up much of the modern Swazi nation.
The country derives its name from a later king, Mswati I. However, Ngwane is an alternative name for Swaziland and Dlamini remains the surname of the royal house, while Nkosi means "king". Scholarly history of Swaziland shows that independent chiefdoms and small kingdoms dominated by various clans were initially conquered and incorporated into the growing Ngwane kingdom ruled by members of the Dlamini clan sometime in the 18th and 19th centuries, long before British colonisation. The Dlamini clan consolidated their hold under several able leaders. The most important was Mswati II, from whom the Swazi derive their name. Under his leadership from the 1840s to 1865, the Swazi expanded their territory to the north and west, and stabilized the southern frontier with the Zulu.
Contact with the British came early in Mswati's reign, when he asked British authorities in South Africa for assistance against Zulu raids into Swaziland. It also was during Mswati's reign that the first whites, Transvaal Boers, ) settled in the country. Following Mswati's death, the Swazis reached agreements with British and South African Republic authorities over a range of issues, including independence, claims on resources by Europeans, administrative authority, and security, though the white parties later reneged on those agreements. Over Swazi protests, the South African Republic with British concurrence established incomplete colonial rule over Swaziland from 1894 to 1899, when they withdrew their administration with the start of the Anglo-Boer War (The Boer Wars (Afrikaans: Vryheidsoorloë, literally "freedom wars") were two wars fought during 1880–1881 and 1899–1902 by the British Empire against the Dutch settlers of two independent Boer republics, the Orange Free State and the Transvaal Republic.) . In 1902 British forces entered the territory, proclaiming British overrule and jurisdiction in 1903, initially as part of the Transvaal. In 1906 Swaziland was separated administratively when the Transvaal Colony was granted responsible government.
Throughout the colonial period from 1906 to 1968, Swaziland was governed by a resident commissioner who ruled according to decrees issued by the British High Commissioner for South Africa. Such decrees were formulated in close consultation with the resident commissioners, who in turn took informal and formal advice from white settler interests and the Swazi royalty. In 1921 the British established Swaziland's first legislative body—a European Advisory Council (EAC) of elected white representatives mandated to advise the British high commissioner on non-Swazi affairs. In 1944, the high commissioner both reconstituted the basis and role of the EAC, and, over Swazi objections, issued a Native Authorities Proclamation constituting the paramount chief or Ingwenyama and King to the Swazis, as the British called the king, as the native authority for the territory to issue legally enforceable orders to the Swazis subject to restrictions and directions from the resident commissioner. Under pressure from royal non-cooperation this proclamation was revised in 1952 to grant the Swazi paramount chief a degree of autonomy unprecedented in British colonial indirect rule in Africa.