Centuries: 1st century BC - 1st century - 2nd century
Decades: 20s BC - 10s BC - 0s - 10s - 20s - 30s - 40s - 50s - 60s - 70s - 80s
30 31 32 33 34 35 36 37 38 39
Sometimes the '30s is used as shorthand for the 1930s, the 1830s, or other such decades in various centuries
