A language goes through greater and smaller modifications. The historical events play an important role in the history of a language. Not only peoples have history, but also languages have historical eras. The certain periods are named after the most characteristic features. In this work the English language is examined in the Anglo-Saxon period. This is the era of Old English. It is important to know, what the circumstances are that contributed to the development, simplification or decline of the language. A language slowly changes on all levels, including phonology, morphology, and syntax. The degree of the modification depends on the historical background to a great extent.