Era
20th century
94
19th century
37
21st century
13
18th century
12
Civil War, 1861-1865
10
Revolution, 1775-1783
7
1564-1616
6
17th century
6
1945-
6
Mesozoic
6
1897-1962
5
Carboniferous
5
Colonial period, ca. 1600-1775
5
Early modern, 1500-1700
5
1817-1862
4
1819-1891
4
1899-1961
4
Cretaceous
4
Eocene
4
Paleozoic
4
Precambrian
4
Tertiary
4
World War, 1939-1945
4
1685-1750
3
1843-1916
3
1873-1947
3
1874-1963
3
1902-1995
3
1917-1963
3
1933-1945
3
1945-1989
3
Early modern and Elizabethan, 1500-1600
3
Quaternary
3
To 1900
3
1588-1679
2
1608-1674
2
1643-1687
2
1661?-1731
2
16th century
2
1812-1870
2
1863-1877
2
1874-1964
2
1878-1967
2
1884-1972
2
1900-1999 (20th century)
2
1902-1968
2
1906-1989
2
1911-1983
2
1926-2005
2
1935-1977
2
more ...