Era
20th century
139
19th century
88
21st century
32
18th century
24
Civil War, 1861-1865
16
16th century
13
1917-1963
12
1945-
11
17th century
10
1564-1616
9
1809-1865
9
1816-1855
9
1818-1848
9
1929
9
1933-1945
9
Revolution, 1775-1783
9
1735-1826
8
1882-1945
7
1820-1849
6
1830-1899
6
1946-
6
Colonial period, ca. 1600-1775
6
1767-1848
5
1775-1817
5
1818-1882
5
1867-1957
5
1960-1980
5
1970-
5
1743-1826
4
1888-1953
4
1924-
4
1945-1989
4
1947-
4
1969-
4
1974-
4
1993-
4
1993-2001
4
2009-
4
To 1500
4
1066-1485
3
1783-1865
3
1797-1851
3
1807-1870
3
1807-1886
3
1838-1918
3
1842-1910
3
1843-1916
3
1848-1892
3
1856-1939
3
1858-1919
3
more ...