1840s, many of the former prazo owners that had survived the droughts and epidemics had left Zambezia and were replaced by five powerful families along the middle Zambezi, the da Cruz, Caetano Pereira, Vas dos Anjos, Ferrão and Alves da Silva, who were joined in the 1860s by a sixth family, the de Sousa. There were also several less prominent Afro-Portuguese families in this area and on the fringes of Portuguese influence. Most of these families were of Indian, or specifically Goanese, origin although the original Alves da Silva were from Portugal, and all of the families based their economy on the slave trade, despite its legal abolition in 1830, or hunting for ivory, rather than agriculture. Through intermarriage with the families of leading African chiefs, they were recognised as the legitimate holders of several chieftaincies by their African subjects and they adopted African titles and the indigenous symbols of kingship and patronised local religious cults, yet also received Portuguese offices or military ranks that gave them an official status. The areas controlled by the main families far exceeded those of earlier prazos, and they maintained large numbers of armed chikunda, said to number several thousand, although estimates vary. Their military strength was based on a combination of strong defensive fortifications and European firearms, including breech-loading rifles later in the 19th century. Their centres were fortified towns, called “aringas”, which were a development of the traditional stockaded village. Each aringa consisted of a wooden stockade, supported by earthworks in the form of a ditch and bank, often with inner walls protecting the more important sections of the town. One large aringa, Massangano, had fortifications 1,300 metres long and 150 to 180 metres wide. These mainly Afro-Goan families formed what were in effect small independent states, giving at best token allegiance to the Portuguese crown. From the 1840s, their leaders attempted to extend their influence, either by forcing neighbouring African chiefs to acknowledge their sovereignty or driving out those that resisted. Several of the less prominent families included the Rosário Andrade, whose head was known as Kanyembe and who operated along the Upper Zambezi west of Zumbo, now the westernmost town in Mozambique, and the Arujo Lobo, whose head was called Matakenya and who operated in the Luangwa and Lower Shire valleys. The chikunda of these two families had a reputation for exceptional savagery, never trading with local peoples but taking