The Phoenicians in the Mediterranean took over Malta from about 1000 BC , using the islands to expand their sea explorations and trade in the Mediterranean , until the Carthaginians took over and also expanded in the Mediterranean , but these were also defeated by the Romans in 216 BC . They used the islands as an outpost from which they expanded sea explorations and trade in the Mediterranean until their successors , the Carthaginians , were ousted by the Romans in 216 BC with the help of the Maltese inhabitants , under whom Malta became a municipium .