In the year 1755, the lower part of the city of Lisbon was hit by a severe earthquake. Immediately following the earthquake a complex reconstruction process began, which introduced new urban, architectural and constructional concepts. This resulted in the creation of new innovative rentable buildings termed the Pombaline rentable buildings, after the Marquis of Pombal who directed their construction. This thesis comprises a wide ranging and detailed study of these buildings. At the beginning of this work, in Chapter I, "The Pombaline rentable building" is placed in its historical context. The origins of the old city are described and its historical development within Portugal. The results and consequences of the 1755 earthquake are outlined, and the subsequent process of reconstruction is described. All immediate measures, decrees, and proposals for the reconstruction of the city, plus Manuel da Maia's Dissertations, are carefully compared and analysed, as are the various plans proposed for the reconstruction. The preceding periods of Portuguese Architecture are studied to identify possible origins for the architecture of the Pombaline rentable buildings. Also a clear definition of the Pombaline Rentable building and the limits of the genuine Pombaline area are established. In Chapter II the general methodology used in the research is described, which includes a survey of 315 buildings and a documentary search for material relating to the construction of the buildings. In Chapter III an analysis is made of the general external and internal architectural characteristics of the rentable buildings. An extensive search for original drawings, produced drawings only of the elevations of the main streets. These are carefully analysed and compared with existing buildings and a classification system is developed. A complete survey by the author of the buildings' interiors, for which no documentary information exists, reveals a great complexity and variety of interior plans. To achieve a systematic classification of the interiors particular aspects are analysed including, the types of stairs, the organization of the interior spaces, the building location and the finishing details. Chapter IV describes some of the technical innovations shown by the rentable buildings, particularly those referring to earthquake resistance in construction and to prefabrication. During the survey of plans and elevations the Author identifies evidence for the existence of prefabrication, in terms of sizes of components, tolerances and detailing. This evidence is supported indirectly by documentary material although the extent of documentation is very limited. vii Possible evidence for an evolutionary development in the internal plan and design of the buildings based upon the position of stairs in the buildings is presented in Chapter V. An attempt is made to relate this classification to the dates of construction of the different buildings. This is achieved by an analysis of previous tax records which enable numbers of buildings constructed on different streets at different periods to be determined. Based on this analysis the evidence for an evolutionary development is discussed. In Chapter VI the Pombaline rentable buildings of Lisbon are compared with other contemporary developments at Porto Cövo, Vila Real and Manique do Intendente in order to assess the influence of the Pombaline development, both in terms of the architecture and the construction processes, on other construction projects outside Lisbon. Chapter VII discusses the principal findings of the research and their importance in the context of Portuguese architecture.