Era
20th century
42
19th century
28
1900-1999
22
1939-1945
18
1800-1899
15
18th century
14
Civil War, 1861-1865
13
21st century
12
1491-1547
9
1700-1799
9
German occupation, 1940-1945
9
1900 - 1999
8
Colonial period, ca. 1600-1775
8
Revolution, 1789-1799
8
1507-1536
7
1533-1603
7
1789-1799
7
1800 - 1899
7
Henry VIII, 1509-1547
7
1789-1793
6
1912-1949
6
British occupation, 1765-1947
6
Revolution, 1775-1783
6
Tudors, 1485-1603
6
-30 B.C
5
16th century
5
17th century
5
1803-1863
5
1865-
5
1881-1936
5
1912-1945
5
1935-2016
5
1944-
5
1949-1976
5
1954-
5
1957-
5
1976-2002
5
519 B.C.-465 B.C. or 464 B.C
5
Commodus, 180-192
5
Qing dynasty, 1644-1912
5
Republic, 1912-1949
5
-1617
4
-480 B.C
4
1162-1227
4
121-180
4
1478-1535
4
150-182
4
1532-1590
4
1580-1631
4
1585-1622
4
more ...