The thesis discusses the architecture of Spain in the Romanesque period with special emphasis on building types Mosque and Basilica. The main buildings are the Great Mosque in Córdoba and religious buildings of Mudéjar-Architecture. The Iberian Peninsula was conquered by Muslim conquerors in the 8th century. Over three centuries, the country was under Islamic rule. The new rulers brought the city of Córdoba for political and religious center. At the site of the Byzantine church was erected a mosque. This structure was continuously enlarged and was one of the most important buildings of the era around 1000 A. D.. In the following years it came to the reconquest of Spain. The country was divided into small city-states. Under the new rule, the remaining Muslims were employed as a designer of civil and religious buildings. The Mudéjar-Architecture so far remained largely unprocessed. The discussion of architectural continuity under changing social conditions should to be answered. The present study focused on the central types and components of Islamic architecture. These include: the horseshoe arch, the ornament, the minaret and the wooden ceiling. The examined sacred buildings showed a combination of Christian and Islamic designs. The outer shape of the basilica and the internal division into main and side aisle were obviously prevalent and the interior, the sculptural adornments on the facade and bell towers but also the use of different arcs shapes on the exterior and in the interior show Islamic elements. There was no discernible hierarchy in the designs. Despite the special status of the remaining Muslims in Spain, in the analyzed buildings here which developed forms were used as coequal. For the studied buildings are no uniform planning. The buildings were partly built over several centuries and change of master builders and craftsmen complicate Architecture Historic Review. Moreover, there are hardly any written sources and archaeological findings document the few historic building history. These and other factors such as modifications in the 19th and 20th centuries, local research literature and the particular situation of the Iberian Peninsula is the only Western European bids with Islamic tradition and culture in the Middle Ages, can research questions unanswered. The present study has identified how the changing cultural, social and religious history has influenced the architecture in the period between middle ages and modern times and expressed in the style of the Mudéjar- Architecture. The Mudéjar-Architecture has no comparisons in Europe and must be recognized as an independent fragile style.