Excerpts from Books and Wikipedia
"For an entire century after 1815, by contrast, there was a remarkable absence of lengthy coalition wars. A strategic equilibrium existed, supported by all of the leading Powers in the Concert of Europe, so that no single nation was either able or willing to make a bid for dominance. The prime concerns of government in these post-1815 decades were with domestic instability and (in the case of Russia and the United States) with further expansion across their continental land-masses. This relatively stable international scene allowed the British Empire to rise to its zenith as a global power, in naval and colonial and commercial terms, and also interacted favorably with its virtual monopoly of steam-driven industrial production." [Kennedy: Great Powers, p. xviii]