“Physiologus”『自然學家』是一部在早期基督文化影響之下（約西元二至四世紀）形成的一部自然百科。每一章描寫一自然界物體的特性，絕大多數是動物，之後緊接著將此特性作基督教的宗教詮釋。事實上它在基督教義詮釋及傳揚的功能遠大於自然科學知識的傳播。本文的主旨是藉由“Physiologus”中對獨角獸的描述及運用，來說明這個源自上古時期基督教的寓意詮釋傳統在中世紀德語文化圈的普遍情況。在介紹『自然學家』這部作品之後，首先要討論的是獨角獸的來龍去脈，然後再比較它在中世紀其他德語文類裡的運用。藉由這些文學證據也可以觀察到這個來自異文化的元素在中世紀德語文學中傳承的情況。 “Physiologus” is a compilation of nature studies, formed at early Christian time (2. – 4. Century A. D.). In every chapter of this compilation, certain of characters of a natural object – predominantly animals – will be described. Following, the descriptions will be interpreted concerning bible passages or the salvific story. However, this opus has its function for Christian edifying instruction more than purpose of biological studies. By means of the motif of the unicorn from the “Physiologus”, diffused in the Middle Age, the progress of the allegorical interpretation regarding the Christian hermeneutics of the Middle Age will be demonstrated. After an introduction into the opus and the studies of the unicorn, its motif history in the literature from the Antique until the German Middle Age will be observed. The applications of this motif in the German literature will be discussed and compared with each other. According to these examples, we will see how a motif comes from a strange culture into the Christian German area and its development there.