North of the Danube the valley of the Naab, at least, was originally Slavonic, containing an extension of the Slavonic population of Bohemia. But disturbance and displacement began early. The Thervings and Grutungs from the north of the Fichtelgebirge made their way to the Danube along these lines. In the third and fourth centuries, the Suevi and Alemanni extended themselves from the upper Rhine. The western parts of Bavaria, on the Wurtemburg frontier, perhaps as Slavonic as the valley of the Naab, differ, in their subsequent history, by having witnessed displacements from the south and west, from the Helvetians of Switzerland, and the Boii of Gaul, rather than from the Germans on the north. The later changes are the same in both cases. The north-western parts of Bavaria were probably German from the beginning. South of the Danube the ethnology changes. In the first place the Roman elements increase; since Vindelicia was a Roman Province. What, however, was the original basis? Probably, Slavonic on its eastern, Helvetian or Keltic on the western side. Its present character has arisen from an extension of the Germans of the upper Rhine. CHAPTER IX. GREAT BRITAIN.--DENMARK.--THE ISLANDS.--THE VITHESLETH.--FYEN.--LAUENBURG.--HOLSTEIN.--SLESWICK.--JUTLAND.--ICELAND. --THE FEROE ISLES.--NORWAY.--SWEDEN.--LAPPS.--KWAINS.--GOTHLANDERS. --ANGERMANNIANS.--THEORY OF THE SCANDINAVIAN POPULATION. As the ethnology of the British Islands is made the subject of a separate volume,[18] the present notice will be confined to the simple statement of the Irish, the Scotch Gaels, the Manksmen, and the Welsh being Kelts, and the English, Germans; the Keltic populations being indigenous, the German, intrusive. Scandinavia comes next in order, the arrangement being strictly natural; since, whatever may have been the original population of Denmark, Norway, and Sweden, the present is of Germanic origin, and speaks a language belonging to the great Gothic class; the Danish and Swedish being mutually intelligible. _The Islands._--The Danish Islands fall into two groups, one containing the Isle of Fyen, the other the ancient _Vithesleth_, or the four islands of Sealand, Laaland, Moen, and Falster. This division is ancient, and in the eyes of some of the older writers of considerable import; since the true country of _Dan_, the eponymus of the _Danes_, was not Jutland, not yet Skaane (the southern part of Sweden), nor yet Fyen. It was the Four Islands of the Vithesleth:--“Dan--rex primo super Sialandiam, Monam, Falstriam, et Lalandiam, cujus regnum dicebatur _Vithesleth_. Deinde super alias provincias et insulas et totum regnum.”--Petri Olai Chron. Regum Daniæ. Also, “Vidit autem Dan regionem suam, super quam regnavit, Jutiam, Fioniam, _Withesleth_, Scaniam, quod esset bona.”--Annal. Esrom. p. 224.