There are a number of theories attempting to explain the origins of Capoeira, all of which have some degree of truth. The original version of the system is thought to have developed from various African cultures and traditions.
One theory speculated that the Mucupes of South Angola (part of the Bantu tribe) sowed the seeds for what would become Capoeira. The Mucupes had an initiation ritual (efundula) for when girls became women. During these occasions young warriors would engage in the ‘N’golo/Engolo’ (Dance of the Zebras) which was a kind of warrior’s fight-dance.
The Mucupes were among many other African tribes affected when their cultures and traditions were uprooted during the horrors of the transatlantic slave trade. The transatlantic slave trade was an oceanic trade in African men, women, and children which lasted from the mid-sixteenth century until the 1860s. European traders loaded African captives at dozens of points on the African coast. These slaves were taken to colonies in the Americas and forced to work in sugar cane fields.
The disenfranchised Mucupes (and other African tribes) bought their unique cultural knowledge with them to the Americas. It included not only knowledge of warrior dances (such as the Engolo) but also of religion, music (the berimbau), food and attitudes. This was an oral tradition (passed on by word of mouth rather than written down) of the engolo and other warrior traditions. These traditions were kept alive, transmitted and shared over generations.
This theory was originally presented by Camara Cascudo (folclore do Brasil, 1967). However, a year later Waldeloir Rego (Capoeira Angola, Editora Itapoan, Salvador, 1968) warned about the lack of evidence to support these claims and invited more research on the matter (sadly no one ever did follow the research up.) It is likely that if Engolo did exist, it would seem that it was at best one of several African dances/traditions that contributed to the creation of early versions of Capoeira.
The traditions transferred around the Americas and in time the techniques found their way to (Portuguese-occupied) Brazil via transported slaves.