 Roman soldiers defended the Rhine and had major armies 100 miles (160 km) south and west of the Rhine.Frankish settlers were established in the areas north and east of the Romans and helped with the Roman defense by providing intelligence and a buffer state.The breach of the Rhine borders in the frozen winter of 406 and 407 made an end to the Roman presence at the Rhine when both the Romans and the allied Franks were overrun by a tribal migration "en masse" of Vandals and Alans.