Approximate Dates
Sources cited in the Syriac Reference Portal frequently give approximate or estimated dates in a variety of prose formats. In order to enable these approximate dates to be processed as machine-readable data, contributors should translate approximate prose dates into ranges with numeric values which reflect the level of precision in the source document.
In general the following prose conventions will be encoded into numeric values according to the following guidelines:
- Xth century -- use an 100-year range
- X-Yth centuries -- use an 100-year range for each century
- first/second half of Xth century -- use a 50-year range
- early/late Xth century -- use a 50-year range
- mid-Xth century -- use a 50-year range
- first/last quarter of Xth century -- use a 25-year range
- beginning of Xth century -- use a 25-year range at the beginning of the century plus an additional 15-year margin into the previous
- end of Xth century -- use a 25-year range at the end of the century plus an additional 15-year margin into the next
These numeric values may be combined as in the following cases:
- Early to mid Xth Century -- use a 75-year range
- late Xth century to early Yth century -- use a 100-year range across two centuries
- late Xth century to first quarter of Yth century -- use a 50-year range at the end of the century plus an additional 25-year margin into the next
NOTE: The ranges corresponding to approximate dates are not mutually exclusive (e.g. early overlaps with mid), nor should they be, since they are by nature not precise information. Accordingly, we have choosen round numbers to begin and end ranges, e.g. 0400-0450 and 0450-0500. The overlap is intended to reflect the imprecision of "first half of the fifth century" which a human author may not intend to end precisely in 0449.
Circa, ?, Floruit, etc.
For dates whose ambiguity has been emphasized by the use of “circa”, “?”, or similar wording, contributors should add additional margins of 15, 25, or 50 years to the dates (contributors may use their discretion in proportion to the size of the date ranges and the uncertainty of the date). Thus “circa Xth century” would be rendered as an 200 year range with 50-year margins on either side of the century in question. Floruit dates should be considered in this same class of highly ambiguous dates. Accordingly a floruit date of “fl. Xth century” should be rendered as an 200-year range, even though the subject is not likely to have flourished for 200 years. Given the highly ambiguous nature of dates in ancient and medieval sources, our editorial preference is to avoid creating a level of precision not supported by the sources.
Exceptions for Precise Dates
These guidelines do not apply when a more precise range for a date is known (e.g. between years x and y). In such a case, these specific years should be used instead of the above ranges.
In general, approximate dates will be encoded into TEI using the @not-before and @not-after attributes (which corresponds to terminus ante/post quem). In cases where specific dates are known or where a choice of date is more appropriate than a range, the @when attribute and multiple <date> elements may be used.
Examples:
| Prose Description | Not-Before Date | Not-After Date | Notes |
|---|---|---|---|
| 4th century | 0300 | 0400 | Full century. |
| 4th century? | 0250 | 0450 | Question mark shows greater uncertainty. |
| probably 4th century | 0250 | 0450 | "Probably" shows greater uncertainty. |
| first half of 5th century | 0400 | 0450 | |
| second half of 6th century | 0550 | 0600 | |
| probably 2nd half of 9th cent. | 0825 | 0925 | "Probably" shows greater uncertainty. |
| mid-7th century | 0625 | 0675 | |
| mid-7th century? | 0610 | 0690 | Question mark shows greater uncertainty. |
| early 8th century | 0700 | 0750 | |
| early 8th century? | 0675 | 0775 | Question mark shows greater uncertainty. |
| late 9th century | 0850 | 0900 | |
| late 9th century? | 0825 | 0925 | Question mark shows greater uncertainty. |
| 10th/11th century | 0900 | 1100 | Two centuries. |
| ca. 10th/11th century? | 0850 | 1150 | Clearly very uncertain. |
| 10th - early 11th century | 0900 | 1050 | |
| late 10th/11th century | 0950 | 1100 | |
| first quarter of 11th century | 1000 | 1025 | |
| last quarter of 12th century | 1175 | 1200 | |
| late 13th - early 14th century | 1250 | 1350 | |
| end of the 14th century | 1375 | 1410 | |
| between 327-335 | 0327 | 0335 | Use dates specified. |
| 826? | 0811 | 0841 | 15 year margin on either side. |
| before 359 | (blank) | 0359 | Terminus ante quem. No way to know how long before. |
| shortly before 1252 | 1237 | 1252 | 15 year margin. |
| after 829 | 0829 | (blank) | Terminus post quem. No way to know how long after. Contributors may, however, add a Not-After end date here by means of inference. For example if a source is reporting on events which have come to conclusion before the publication of the source, the Not-After date may be inferred to be at least the publication date of the source. |
| shortly after 1587 | 1587 | 1602 | 15 year margin |
| probably after 829 | 0814 | (blank) | Not certain date is after 829, so 15 year margin before. |
| ca. 1842 | 1827 | 1857 | 15 year margin on either side. |
| ca. 381? | 0356 | 0406 | Question mark shows greater uncertainty: 25 year margin on either side. |
| ca. 491-496 | 0476 | 0511 | 15 year margin on from each end of the range. |
| ca. 13th century | 1150 | 1350 | |
| between the 10th and beginning of the 13th cent. | 0900 | 1225 | Quite a range! |
| around the end of the 16th and the first decades of the 17th cent. | 1575 | 1630 | |
| 1864/5 | 1864 | 1865 | One year or the other. Note: This only applies to consecutive dates. |
| 1887/1890 | 1887 | 1890 | |
| 200? | 2000 | 2009 | This use of the ? can be misleading. It does not mean "perhaps 200" but rather "2000-something." This usage is rare, so contributors should consult with an editor on how to encode. |