2.3.7.1 Format of Dates

Dates should normally be written in day-month-year order. This form is widely understood internationally and avoids the extra commas required by month-day-year style. Avoid all-numeric dates, since forms such as 4/8/1904 may be read differently by different audiences.

Preferred

• 8 April 1904
• March 1909
• April 814 CE
• Junius (June) 493 BCE

If month-day-year style is used, include the comma after the day and, when the sentence continues, after the year.

Acceptable, but not preferred

• April 8, 1904
• Crowley arrived in Cairo on April 1, 1904, before the reception of the Book of the Law.

Centuries

Use spelled-out ordinal forms for named centuries, and lowercase the expression unless it begins a sentence or appears in a title. Numeral forms may also be used where appropriate, especially for broad historical periods such as the 1800s or 1900s. Do not use an apostrophe before the s. Either form is acceptable, but the choice should be applied consistently within the same discussion or comparable contexts.

Examples

• the twenty-first century
• the eighth and ninth centuries
• from the ninth to the eleventh century

but

• the 1800s and 1900s, or
• the nineteenth and twentieth centuries

Avoid potentially unclear expressions such as the turn of the twenty-first century. Use the turn of the century only when the relevant century is unmistakable from the surrounding context.