谁能帮我找找关于中世纪庄园和城堡的文章(要英文的)

谁能帮我找找关于中世纪庄园和城堡的文章(要英文的)
介绍中世纪庄园和城堡的文章,要英文的.
比如介绍它的历史,由来,庄园制度等

介绍三个关于中世纪庄园和城堡的文章.如不能打开网站,请来信告知.
Castles Along the Rhein River
From Cologne to Mainz
INTRODUCTION
The castles which are today such an unmistakable feature of the Rhein landscape date back to the Middle Ages.Their founders were feudal overloards,who,so far from cherishing any romantic notions,built them with one simple aim in mind:to protect their lands from marauders and predatory neighbours.They chose mountain-tops as strategically ideal situations,and we today,looking back through the haze of ninteenth-century medievalism,are still often prone to see them as objects of mystery and splendour,forgetting the warlike function for which they were built and the back-breaking labour of the feudal serfs,whom we must presume to have been forcibly employed in quarring the huge stone blocks and dragging them up the mountain slopes.
Since Roman times the Rhein valley has been a line of communication of vital strategic importance.In the Middle Ages the German emperors used it for their frequent progresses into Italy,and rich merchants sent their goods to and fro along it.Obviously anyone owning a castle overlooking the valley was in a powerful position,since he was able to survey and regulate the flow of traffic across his particular territory and levy tolls on merchants.This accounts for the large number of castles along the Rhein from Mainz to Bonn,particularly in the narrow gorge connecting Bingen and Koblenz.Along this stretch of river,which has a length of only thirty-five miles,there are more castles than in any other river valley in the world.