In the history of Vanuatu, the commonly held theory of Vanuatu's prehistory from archaeological evidence supports that peoples speaking Austronesian languages first came to the islands some 4,000 to 6,000 years ago.[31] Pottery fragments have been found dating back to 1300 BC[32] What little is known of the pre-European contact history of Vanuatu has been gleaned from oral histories and legends. One important early king was Roy Mata, who united several tribes, and was buried in a large mound with several retainers. The first European contact with Vanuatu came in 1606, when a Spanish expedition led by the Portuguese explorer Pedro Fernández de Quirós discovered Espiritu Santo, naming it Australia del Espiritu Santo, believing he had arrived in the southern continent.