自從18世紀末至19世紀初，在德意志浪漫主義思潮的波及及拿破崙大軍佔領德意志全境而引發了德意志民族主義的浪潮之後，使得德人因而往溯歷史上自身民族的輝煌史蹟，試圖建構對抗外來佔領的精神戰力，遂使直到19世紀初才被史學界發現並珍視的「中世紀德意志人東向移民拓殖史」，迅即被視為歷史典範而歌頌之。其後在19世紀初期至中期所進行的德意志民族統一運動的過程中，基於訴求未來民族國家同質化的要求下，這段史實屢屢被德人用來作為同化波蘭人的工具，認為中古時期德人在移民拓殖於中東歐地區時所同化大批斯拉夫人的歷史，可作為當前在德意志東部所進行的日耳曼化政策的典範，遂使該史實沾染濃厚民族主義的色彩。在德意志第二帝國於1871年締建之後，該史實除了在內政上被繼續充當同化波蘭人的工具之外，亦在1890年代所展開的世界政策中，被賦予了對外功能而運用，即充作德意志第二帝國東向擴張及完成德意志人的東部帝國主義之夢的宣傳工具。其後隨著一戰的爆發及德軍在東線戰場的連番大捷，進一步使得這段中古時期的史實，完全淪為第二帝國在中東歐及東歐地區推行其佔領暨殖民政策時的最佳歷史宣傳題材。本文將在簡述中古德意志人東向移民拓殖史的本質內涵後，旋以這段史實作為德意志第二帝國東進行動的指導原則，以及作為第二帝國東向擴張及東部帝國主義的宣傳工具為題，探究其發展始末。

German nationalism was evoked by the German Romanticism and the conquer by Napoleon Wars from the end of 18^(th) century to the beginning of the 19^(th) century. The Germans therefore attempted to consolidate their spirits against the defeat from without by means of appealing to their national glorious historical past. Until the launch of the 19^(th) century, ＂History of German Eastern Migration and Colonization in the Middle Ages＂ was then discovered and treasured, and it was seen as historical paradigm and was praised. Thereafter in the process of German national unity movement, this period of history was utilized to assimilate the Poles in order for national homogeneity. The history in which numerous Slavs in Central Eastern Europe were assimilated by the Germans in the middle ages was deemed the model of the Germanization policy, so that nationalism prevailed strongly. After the German Second Reich was built in 1871, the aforementioned history was interiorly not only employed to assimilate the Poles, but also exteriorly as the propaganda tool to expand eastward and to accomplish the Germans' Eastern Imperialism since 1890s. Upon the burst of the World War I and the sequential success in Eastern Front made this period of medieval history completely the best propaganda history, with which the Second Reich occupied and colonized in Central Eastern Europe and Eastern Europe. This study describes the essence of the German Eastern Migration and Colonization in the Middle Ages, and analyzes the process in which the propaganda tool of Eastern Expansion and Imperialism was employed.