Berlin Conference of 1884-85 and its requirement for effective occupation rather than claims based on early discovery or more recent exploration. In 1880 Manuel António de Sousa, who has previously married a member of the royal family of Barue, which was adjacent to his statelet in Gorongosa, occupied Barue after the death of its ruler. As Barue lay close to both the land route from Sena to Tete and the territory of the da Cruz family, the existence of an unfriendly ruler in Barue, particularly one in alliance with the da Cruz, could block any Portuguese attempts to link Angola and Mozambique. The de Sousa family had been allied with the Portuguese forces attacking Massangano, and the Portuguese government approved of Manuel António's occupation of Barue, although de Sousa did not recognise Barue as part of Mozambique. De Sousa built around thirty aringas in Barue and manned them with his chikunda. In 1884, he again made himself valuable to the government in helping to put down a revolt by supporters of the Vas dos Anjos, reportedly sending 10,000 of his chikunda against these rebels The activities of the Rosário Andrade and Arujo Lobo families along the Upper Zambezi prompted the Portuguese government to lay claim to the Upper Zambezi valley as far as the Sanyati River, now within Zimbabwe. By the late 1870s, both these families had pledged a vague loyalty to the Portuguese Crown, and the Vas dos Anjos had been forced to submit to Portugal in 1884, leaving the da Cruz family at Massangano as the most prominent minor state in the area claimed by Portugal that insisted on its complete independence from the Portuguese Crown. Following the Berlin Conference, this could leave the da Cruz territory open to a British takeover, if it accepted British protection and there were indications it might do so. Manuel António de Sousa did not formally claim to be king of Barue but did attempt to extend his territory into the high veldt of Mashonaland in 1886, absorbing the Shona chieftainship of Rupire in the area of the former Mazoe goldfields, which had been productive in the 17th century. However, his chikunda failed to defeat the Mtoko chieftainship in the same area at the start of 1887. De Sousa was distracted from attempting a further attack on Mtoko by a renewal of the war against the da Cruz, who reacted to being