This is a study of the reasons for two long periods of peace between the European great powers, 1815-54 and 1871-1914, and the reasons for their breakdown. Special attention is paid to the limitations of the Concert of Europe and Balance of Power in making for peace. An imbalance in favour of the status quo was more important. Thus France was easily isolated in the years 1815-52, while Germany from 1871 until c. 1905 chose not to use her economic and military advantages to promote territorial revisionism in Europe.