Portals and External Doors in Hessian Stately Homes of the Baroque Period In historic buildings, alternating construction stages spread out over the centuries usually result in a melange of various building styles. The professional and appropriate treatment of individual structural segments within the framework of a required redevelopment hence calls for detailed knowledge of the decorative and constructional characteristics of the various architectural periods involved. Modifications are particularly conspicuous in the front door area, where historically inappropriate interventions might disturb the façade’s harmonious appearance. That the dissertation in hand takes the investigation of this indispensable component as its subject is hence owed to the significance of the main entry as an element of façade design and development. The dissertation's objective is the concretization of portal design characteristics in the baroque age. The structural framework of the door opening is just as typical in this as the wooden door leaf and its metal garnishments are. The design principles of architectural theory will, besides Vitruvius’ De arcitectura libri decem, mainly be culled from Italian tractates of the Renaissance and baroque period and supplemented by elucidations contained in French and German writings of the time. Using Hessian stately homes from the period 1680 to 1770 as examples, the typical features of practical portal design will be portrayed and described in detail. The comparison between the theoretical principles and the examined portals will shed light on the scope and manner in which architectural theory has been integrated in baroque construction practice.