Malta was then ruled by Byzantine, a Greek group that took over almost all of the Mediterranean, from the 4th to 9th century. Sometime around this point, the Vandals, a German tribe, ruled the islands. The islands were at one point invaded by the Arabs in AD 870. They allowed the people to believe in Christianity, and did not have children with the population, so they did not change much on the island, but they showed them citrus fruits and cotton, and water-moving systems. They hardly had any effect on the island or its people while they were there, but one thing that they did effect was the language. The Maltese language gained a lot from this.