Era
Cretaceous
24
Jurassic
12
1895-1974
8
20th century
7
1891-1973
6
1788-1824
5
1960-
5
Tertiary
5
1497?-1543
4
1735-1788
4
1881-1958
4
1887-1927
4
1959-
4
19th century
4
Permian
4
Quaternary
4
To 1848
4
1549?-1624
3
1840-1931
3
1943-1955
3
1948-
3
1964-
3
John II, 1406-1454
3
Mesozoic
3
Miocene
3
Paleocene
3
Triassic
3
1405-1454
2
1921-2003
2
1931-1939
2
1949-
2
1955-
2
1955-1983
2
1962-
2
1963-
2
1965-
2
Civil War, 1936-1939
2
Classical period, 1500-1700
2
Mississippian
2
Oligocene
2
To 1846
2
approximately 1283-approximately 1350
2
-1453
1
-1548
1
-1578
1
-1625
1
-1781
1
-1792
1
1282-1347
1
1411-1456
1
more ...