ISO Examples from BL Guide DateISO th April April [note hyphen] th century18 65 AD BC-0360 [note difference of one] 8/13/2013BL Guide 1

EDTF Examples from BL Guide DateExtended Date/Time Format 1990?1990? ‡2 edtf approximately ~ ‡2 edtf 1860 or 1861 [1860,1861] ‡2 edtf between 1930 and ‡2 edtf between 1890 and u ‡2 edtf (or, unknown year for the same period)189x ‡2 edtf 8/13/2013BL Guide 2 [BL]: Note the difference between u, where there is an expectation that the precise year might become known, and x, where there is not.

8/13/2013 BL Guide 3 Personal Names (9.3.; PS ) [BL] Record as appropriate a date of birth and/or a date of death, or a date or dates indicating a person’s period of activity. Record as specific a date as is known, even if a less specific date, or no date, has been used as an addition to the preferred name in the authorised access point: 046 __ ‡f _ Smith, John, ‡d If only the year is known, record only the year: 046 __ ‡f _ Munro, Alice, ‡d 1931-

8/13/2013 BL Guide 4 Active Dates [BL] Record “active” dates in subfields ‡s and ‡t. Record a single “active” date in subfield ‡s: 046 __ ‡s 1820 ‡t _ Smith, John, ‡d active __ ‡s _ Wills, Benjamin (Surgeon) Note that the century when a person was active can be recorded in 046: 046 __ ‡s _ Parish, C. H. (person active in 19th century)

Active Date Examples [BL Guide] Date046 Formulation active 18th century (1700s) ‡s 17 active 1730‡s 1730 active ‡s 1730 ‡t 1750 active active 20th century‡s 19 active 20th-21st centuries‡s 19 ‡t 20 8/13/2013BL Guide 5 [BL:] Best practice is to include an 046 for a personal name, even if dates of birth and/or death are unknown, to indicate the year, years, century or centuries in which a person was active: