Era
1945-
11
Civil War, 1861-1865
6
Revolution, 1775-1783
5
18th century
3
1933-1945
3
1973-
3
20th century
3
Colonial period, ca. 1600-1775
3
1809-1817
2
1809-1865
2
1819-1892
2
1914-
2
1918-1945
2
1945-1980
2
1979-
2
19th century
2
Constitutional period, 1789-1809
2
Occupation, 1939-1945
2
To 1775
2
(1650-1719)
1
1473-1543
1
1600-1699
1
1648-1789
1
1656-1680
1
1714-1738
1
1732-1799
1
1760-1789
1
1762-1878
1
1781-1869
1
1783-1865
1
1789-1815
1
17th century
1
1816
1
1822-1893
1
1823-1897
1
1837-1901
1
1865-1898
1
1871-1918
1
1874-1952
1
1893-1977
1
1922-
1
1933-
1
1935-
1
1940-1991
1
1945-1955
1
1945-1991
1
1948-
1
1949-
1
1968-
1
1969-1974
1
more ...