The Frisii were among the migrating Germanic tribes that settled along the North Sea in the 4th century BC. They came to control the area from roughly present-day Bremen to Bruges, and conquered many of the smaller offshore islands. In the 1st century BC, the Frisii halted a Roman advance and thus managed to maintain their independence. In the Germanic pre-Migration Period (i.e., before c. 300 AD) the Frisii and the related Chauci, Saxons, and Angles — so closely related that their languages were probably mutually intelligible, Old Frisian considered the closest language to Old English — inhabited the Continental European coast from the Zuyder Zee to south Jutland. All of these peoples shared a common material culture, and so cannot be defined archaeologically. On the east they were originally bordered by the Ampsivarii who lived at the mouth of the Ems until AD 58, at which time the Chauci expelled them and gained a border with the Frisii.