The western fringe of the Iberian Peninsula was inhabited from 8000 BC by Neolithic peoples known as Iberians. Celtic tribes settled in the north and west of the peninsula in the first millennium BC with Phoenician settlements in the southwest around Cádiz from around 800 BC. From 241 BC the Iberian Peninsula came under the influence of Carthage, and then Rome after 206 BC. The Romans made their way north to what is now central Portugal and clashed with a Celtic federation, the Lusitanians. They resisted the Roman advance under their leader Viriathus until he was killed in 140 BC, after which the Romans were able to move north across the Douro river. In 25 BC Augustus founded Augustus Emirita (now Mérida) as the capital of Lusitania.