Columbia subject headings:
Diplomacy.
Europe--Foreign relations--1815-1871.
Europe--Foreign relations--1871-1918.
Europe--Politics and government--1815-1871.
Europe--Politics and government--1871-1918.
World politics--1900-1918.
World politics--19th century.
Harvard subject headings:
Diplomacy.
Europe--Foreign relations--1815-1871.
Europe--Foreign relations--1871-1918.
Europe--Politics and government--1815-1871.
Europe--Politics and government--1871-1918.
World politics--1900-1918
World politics--19th century
Princeton subject headings:
Diplomacy.
Europe--Foreign relations--1815-1871.
Europe--Foreign relations--1871-1912.
Europe--Politics and government--1815-1871.
Europe--Politics and government--1871-1918.
World politics--1900-1918.
World politics--19th century.