Leil's son Rud Hud Hudibras reigned for thirty-nine years after him. Once the civil war was over, Hudibras restored peace once more to the people. It was he who built Kaerreint: that is, Canterbury. He also founded Kaerguenit, or Winchester, and the fortress of Paladur, which is now called Shaftesbury. There the eagle spoke, while the wall was being built. If I believed its Sayings to be true, I would not hesitate to hand them down to history with my other material. [II.9]
Alan thereupon took a number of books, such as the one about the Auguries of the Eagle which had prophesied at Shaftesbury and those on the oracular Sayings of the Sybil and of Merlin. [XII.18]
SHAFTESBURY is represented by various forms in the manuscripts of the Historia (for example, Sephtonia, Sestonia). Tatlock points out that Geoffrey's Latin version, oppidum Paladur, is really just a translation of the English name, because paladyr is Welsh for spear (while oppidum translates the common Saxon ending -bury, from burgh, settlement). He suspects that both the Celtic name and the prophetic eagle may be Geoffrey's inventions, though he does not completely discount the possibility of pre-existing tradition. Some manuscripts use the form oppidum montis paladur, and Tatlock points out that this is probably the correct reading, since it was Shaftesbury's elevated location that led the Saxons to establish a settlement there (pp. 43-45).
For further information about Shaftesbury, visit the Shaftesbury Abbey site. There are photographs of the area on the Images of Dorset site.