Only one hypothesis seems to remain, which is that it is a tomb of the northern men who conquered these islands in the ninth century. This may seem a very prosaic descent from the primæval antiquity some are inclined to ascribe to these monuments, but it certainly is not improbable; in the first place, because we have what seems undoubted testimony that Thorfin, one of the Jarls (940 to 970 A.D.) "was buried on Ronaldshay under a tumulus, which was then known by the name of Haugagerdium, and is perhaps the same as that we now call the How of Hoogsay," or Hoxay.[282] I have not been able to ascertain whether this is literally true or not, but have reason to believe that it was not in the How of Hoxay that Thorfin was buried, but in a mound close by.[283] The fact of his being buried in a Howe is, however, all that is at present demanded. Another important barrow is mentioned by Professor Munch,[284] known as Halfdan's Barrow, in Sandy, and raised by Torf Einar (925 to 936). So that we know of at least two important barrows belonging to the Norwegian Jarls in the tenth century, though only one has been identified with absolute certainty. As before mentioned, it is quite certain that King Gorm (died 950) and Thyra of Denmark were buried in tumuli in outward appearance very similar to Maes-Howe. That of Queen Thyra has alone been opened. It is a chamber tomb, similar to Maes-Howe, except in this, that the chamber in Denmark is formed with logs of wood, in the Orkneys with slabs of stone, but the difference is easily accounted for. At Jellinge stone is rare, and the country was covered with forests. At Stennis self-faced slabs of stone were to be had for the lifting, and trees were unknown. The consequence was, that workmen employed the best material available to carry out their purpose. Be that as it may, the fact that kings of Denmark and Jarls of Orkney were buried in Howes in the tenth century, takes away all _à priori_ improbability from the hypothesis that Maes-Howe may be a sepulchre of one of those Northmen.