Moshoeshoe was the son of a minor chief of the Bakoteli lineage- a branch of the Koena (crocodile) clan. In his early childhood, he assisted his father get power over some other smaller clans. At the age of 34 Moshoeshoe formed his own clan and became a chief. He and his followers settled at the Butha-Buthe Mountain.
Moshoeshoe’s reign coincided with the growth to power of the well-known Zulu king, Shaka. During this first part of the 1800s, Shaka raided many smaller clans along the Eastern coast of Southern Africa incorporating parts of them into his steadily growing Zulu chiefdom. Various small clans were forced to flee the wrath of the Zulu chief. Then an era of great wars of calamity followed. It was marked by a lot of aggression and ruin against the Sotho people by the invading Nguni clans. The attacks also forced Moshoeshoe to move his settlement to the Qiloane plateau. The name was later changed to Thaba Bosiu or "mountain of the night" because it was believed to be growing during the night. It proved to be an impassable stronghold against enemies.
The most significant role Moshoeshoe played as a diplomat was his acts of friendship towards his beaten enemies. He provided land and protection to various people and this strengthened the growing Basotho nation. His influence and followers grew with the integration of a number of refugees and victims of the wars of calamity.
By the latter part of the 1800s, Moshoeshoe established the nation of the Basotho. He was popularly known as Morena e Moholo/morena oa Basotho (Great chief/king of the Basotho).
Around the 1830s, the Europeans started to move into the mainland of South Africa. Firstly, this led to missionaries from various societies setting up missions with different clans throughout the country. However, this period also marked the beginning of conflict between Europeans and African tribes. The Afrikaners, the Dutch-speaking people of mixed European descent, met the Basotho after they settled in the region of the now Free State province (bordering Lesotho on the west). In an attempt to be prepared for any possible battle, Moshoeshoe ask the missionaries to come and live among his people. He believed that in this way, it would be easier to acquire guns for protection against the Europeans and the Khoikhoi people. The missionaries introduced many new things to the Basotho society in terms of religion, western thought and even livestock and food. The first three missionaries were Thomas Arbousset, Eugene Casalis and Constant Gosselin from the Paris Evangelical Missionary Society (PEMS). They were placed at Morija, where a lot of work was done on creating orthography for the Sesotho language. The first printing press was also established here. Casalis also acted as an advisor to King Moshoeshoe in terms of matters relating to Europeans.
For strategic reasons and mainly for protection against Afrikaners, Basotho became allies with the British Cape Colony in 1843. During the period that followed many wars and conflicts took place between the Basotho, the Afrikaners and English. This happened at the backdrop of increased colonization in Africa by Britain and shifts in possession of the Free State region between the Afrikaners and the British.
The British annexed Lesotho, the then Basutoland, in 1868 and it led to British rule up to independence on 4th October 1966.