# 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 always should be provided in full.1000–1005, 1005–1015, 1950–19.76
**3.4** For calendar dates we use the US format.January 1, 2023
**3.5** Decades are formed by adding a plural -s1950s, 870s
**3.6** Abbreviated years may be used if they are clear from context.1950s, ‘60s, and ‘70s
**3.7** For approximate years, use c. (circa).Palladio's Palazzo Chierecati (c. 1550)