3. Dates
3.1 For the Gregorian calendar we prefer BCE/CE abbreviations.
3.2 Centuries should be spelled out fully in main prose.
sixteenth century, eighth-century manuscript, early fifth-century vase
3.3 Date ranges follow the same rule as page ranges.
1000–1005, 1005–15, 1950–76
3.4 For calendar dates we use the US format.
January 1, 2023
3.5 Decades are formed by adding a plural -s
1950s, 870s
3.6 Abbreviated years may be used if they are clear from context.
1950s, ‘60s, and ‘70s