The title of Mwene Mutapa, meaning "Ravager of the Lands", was bestowed on him and subsequent rulers. The Mutapa Empire ruled territory between the Zambezi and Limpopo rivers, in what is now Zambia, Zimbabwe and Mozambique, from the 14th to the 17th century. By its peak, Mutapa had conquered the Dande area of the Tonga and Tavara. The Mutapa Empire predominately engaged in the Indian Ocean transcontinental trade with and via the WaSwahili. They primary exported gold and ivory for silk and ceramics from Asia. Like their contemporaries in Maravi, Mutapa had problems with the arriving Portuguese traders. The peak of this uneasy relationship was reached when the Portuguese attempted to influence the kingdoms internal affairs by establishing markets in the kingdom and converting the population to Christianity. This action caused outrage by the Muslim WaSwahili living in the capital. This chaos gave the Portuguese the excuse they were searching for to warrant an attack on the kingdom and try to control its gold mines and ivory routes. This attack failed when the Portuguese succumbed to disease along the Zambezi river. In the 1600s, internal disputes and civil war began the decline of Mutapa. The weakened kingdom was finally conquered by the Portuguese and was eventually taken over by rival Shona states. It is hypothesised by Julian Cobbing that the presence of early Europeans slave trading and attempts to control resources in various parts of Bantu Speaking Africa caused the gradual militarization of the people in the region. This can be observed with the Maravi's WaZimba warrior cast who, once defeating the Portuguese, remained quite militaristic afterwards. The Portuguese presence in the region was also a major reason for the founding of the Rozvi Empire, a breakaway state of Mutapa. The ruler of the Rozvi, Changamire Dombo, became one of the most powerful leaders in South-Central Africa's history. Under his leadership, the Rozvi defeated the Portuguese and expelled them from their trading posts along the Zambezi river. But perhaps the most notable instance of this increased militarization was the rise of the Zulu under the leadership of Shaka. Pressures from the English colonialists in the Cape and increased militarization of the Zulu resulted in the Mfecane (the crushing). The Zulu expanded by assimilating the women and children of tribes they defeated, if the men of these Nguni tribes escaped slaughter, they used the military tactics of the Zulu to attack