In recent decades, East and South-East Asia have became both politically and economically significant for the West and it is no longer possible to ignore the history and culture of this large portion of the world's population. Advanced studies on the various aspects of the rich heritage of these civilisations will contribute to a better understanding of the aspirations and strength of these countries as well of their cultural and historical antecedents and social limitations. The achievements of Korean civilisation are still largely unknown in the West and Korean Buddhist architecture is no exception to this rule. The present thesis discusses the earliest evidence of Buddhist architecture on the Korean peninsula and thus tries to establish a basis on which future studies on Korean architecture can be built. The discussions of the relationship between the Buddhist architecture of the Korean peninsula and that of the Chinese mainland and the Japanese archipelago lead to a reappraisal of the place of early Korean Buddhist architecture in the history of world architecture on an equal footing with that of China and Japan. The thesis is divided into five chapters, the first of which introduces the history and culture of Korea before the introduction of Buddhism. The second to fourth chapters present the historical and material evidence of Buddhist architecture in the early Korean kingdoms of Ko-gu-ryo (Chapters 2.1 and 2.2.), Baek-che (Chapters 3.1. and 3.2.) and Ka-ya and Ancient Sin-la (Chapters 4.1. and 4.2.). The characteristics of the various traditions and their relationships to China and Japan are explored in the last part of each chapter (Chapters 2.3., 3.3. and 4.2.). The time scale of the study stretches from the introduction of Buddhism into Ko-gu-ryo in the late fourth century AD to the unification of the larger portion of the peninsula by Sin-la in the middle of the seventh century AD. This period of Korean history is commonly called the Three Kingdoms' period in spite of the fact that until the middle of the sixth century four political entities shared the Korean peninsula. The conclusions form the fifth chapter which includes a summary of the main results (Chapter 5.1.), a comparison of the Buddhist architectures of the Korean Three Kingdoms period (Chapter 5.2.), discussions of the "archetypes" of East Asian Buddhist architecture and the development of the temple layout types in Korea (Chapter 5.3. and 5.4.), as well as an assessment of the various influences on the development of temple layouts and Buddhist architecture in Korea (Chapter 5.5.). The main results of the study are as follows. The Buddhist architectural traditions of Ko-gu-ryo and Baek-che were directly introduced from the Chinese mainland. While many typical Chinese architectural elements were shared by the Buddhist architectures of both these Korean kingdoms (site selection, polar organisation, wooden skeleton structure, tile roofs, etc.), the differences of temple layout and of building types of the central pagodas indicate that the Buddhist architectures of the two kingdoms originated from different Buddhist architectural traditions in China (possibly a "northern" and a "southern" tradition ?). The Buddhist architectures of Ancient Sin-la and early Japan, however, represent a later stage of development which can be characterized by a combination of elements of various traditions including those of Ko-gu-ryo and Baek-che, and possibly some additional Chinese ones which are still largely unknown. A survey of the main developments of the Buddhist architecture of Korea in later periods would show that many of them can be traced back to the Three Kingdoms period. Such elements are the "courtyard-centered" temple layout of the "mountain temples" of the Cho-son period (1392 - 1910 AD) and the "miniature" Stone and brick pagodas which were particularly popular in the Unified Sin-la period (668 - 935 AD). Three "spheres of influence" have contributed to the development of Korean Buddhist architecture: Indian Buddhism has provided the religious and philosophical doctrines, the monastic order and a large part of the iconography; Chinese civilisation has contributed its social and ethical system, the "courtyard architecture" and the wooden construction system with tile roofs; the local Korean culture, by filtering and developing these influences and by combining them with typical Korean elements, succeeded in creating an original architectural tradition which can be considered one of the most balanced in East Asia. The study shows that Korean culture in general and its architecture in particular was already highly developed and featured a number of specifically "Korean" characteristics by the end of the Three Kingdoms period in the early seventh centuries AD. The deep Chinese and Buddhist influences on the one hand and a constant effort to preserve cultural and political independence from China and Japan on the other hand are two of the most remarkable aspects of Korean civilisation. This double aspect of Korean culture is supplemented by a high degree of creativity in various fields of science and art in which Buddhist architecture occupies a prominent place.