Frankish, (and later Dutch, Luxembourgish and the Frankish dialects of German in Germany) has continuously been intelligible to some extent with both "Ingvaeonic" Low German, and some "Suebian" High German dialects, with which they form a spectrum of continental dialects. All these dialects or languages appear to have formed by the mixing of migrating peoples after the time of Julius Caesar. So it is not clear if these medieval dialect divisions correspond to any mentioned by Tacitus and Pliny. Indeed, in Tacitus (Tac. Ger. 40) and in Claudius Ptolemy's "Geography", the Anglii, ancestors of the Anglo-Saxons, are designated as being a Suebic tribe. Despite their common linguistic framework, by the 5th century CE, the Germanic peoples were linguistically differentiated and could no longer easily comprehend one another. Nonetheless, the line between Germanic and Romance peoples in central Europe remained at the western mouth of the Rhine river and while Gaul fell under Germanic domination and was firmly settled by the Franks, the linguistic patterns did not move much. Further west and south in Europe-proper, the linguistic presence of the Germanic languages is almost negligible. Despite the fact that the Visigoths ruled a kingdom in what is now Spain and Portugal for upwards of 250 years, there are almost no recognizable Gothic words borrowed into Spanish or Portuguese. By 500 CE, the West Germanic speakers had apparently developed a distinct language continuum with extensive loaning from Latin (due to their ongoing contact with the Romans), whereas the East Germanic languages were dying out. Germanic literature includes all the oral and written literature which was common to the early Germanic peoples, in respect to form and nature of content. It was generally intended to honor the gods or to praise tribal ancestors. The general public plays an insignificant role in Germanic literature, which revolves almost exclusively around chieftains, warriors and their associates. Wives and other female relatives of such leaders and warriors figure prominently in many pieces of Germanic literature. Germanic literature is divided into literature transferred orally from generation to generation and literature written down at a later date. Some of this literature, such as the Grottasöngr, appears to have been passed down from a very early time. Much of what is known about Germanic literature was passed down by skalds and scops, who were poets employed by a chieftain to memorize his deeds and those of his ancestors.