Southern Africa in 1750 consisted of small chiefdoms that were ruled by chiefs and engaged in trade. By the mid-18th century, the region had not been greatly affected by European colonialism. However, from around 1750, the societies underwent a period of transformation known as the "time of troubles" or "Mfecane" where there were major political and social upheavals, wars, and migrations. The causes of this period were complex, but included some chiefdoms growing more powerful and tensions increasing, as well as expanding European colonial settlements placing more pressure on indigenous groups.