Opposite this hypothetical gate-way stood the Five-cornered tower. The lower part dates, we have seen, from no earlier than the eleventh century. It is referred to as Alt-Nürnberg (old Nuremberg) in the Middle Ages. The title of "Five-cornered" is really somewhat a misnomer, for an examination of the interior of the lower portion of the tower reveals the fact that it is quadrangular. The pentagonal appearance of the exterior is due to the fragment of a smaller tower which once leaned against it, and probably formed the apex of a wing running out from the old castle of the Burggrafs. The Burggräfliche Burg stood below, according to Mummenhof, southwest and west of this point. It was burned down in 1420, and the ruined remains of it are supposed to be traceable in the eminence, now overgrown by turf and trees, through which a sort of ravine, closed in on either side by built-up walls, has just brought us from the town to the Vestner Thor. The Burggraf's Castle would appear to have been so situated as to protect the approach to the Imperial Castle (Kaiserburg). The exact extent of the former we can not now determine. Meisterlin refers to it as a little fort. We may, however, be certain that it reached from the Five-cornered tower to the Walpurgiskapelle. For this little chapel, east of the open space called the Freiung, is repeatedly spoken of as being on the property of the Burggrafs. Besides their castle proper, which was held at first as a fief of the Empire, and afterward came to be regarded as their hereditary, independent property, the Burggrafs were also entrusted with the keeping of a tower which commanded the entrance to the Castle rock on the country side, perhaps near the site of the present Vestner Thor. The guard door may have been attached to the tower, the lower portion of which remains to this day, and is called the Bailiff's Dwelling (Burgamtmannswohnung). The exact relationship of the Burggraf to the town on the one hand, and to the Empire on the other, is somewhat obscure. Originally, it would appear, he was merely an Imperial officer, administering Imperial estates, and looking after Imperial interests. In later days he came to possess great power, but this was due not to his position as castellan or castle governor as such, but to the vast private property his position had enabled him to amass and to keep.