From c. 1200-800 BCE Austronesian Lapita people began arriving from the Bismarcks with their characteristic ceramics. Evidence for their presence has been across the Solomon archipelago, as well at the Santa Cruz Islands in the south-east, with different islands being settled at different times. Linguistic and genetic evidence suggests that the Lapita people "leap-frogged" the already inhabited main Solomon Islands and settled first on the Santa Cruz group, with later back-migrations bringing their culture to the main group. These peoples mixed with the native Solomon Islanders and over time their languages became dominant, with most of the 60-70 languages spoken there belonging to the Oceanic branch of the Austronesian language family. Then as now communities tended to exist in small villages practising subsistence agriculture, though extensive inter-island trade networks existed. Numerous ancient burial sites and other evidence of permanent settlements have been found from the period 1000-1500 CE throughout the islands, one of the most prominent examples being the Roviana cultural complex centred on the islands off the southern coast of New Georgia, where a large number of megalithic shrines and other structures were constructed in the 13th century.