Dating to years:
| == | May have occurred at any time during the current year |
| >> | Occurred either this year or early in the following year |
| << | Occurred either this year or in the previous year |
| ?? | Occurred either this year or in an earlier year, for instance an unknown year during a war or reign |
| ++ | A "continuous" event spread over many years, for instance a life or reign |
Dating to months:
| -B | Babylonian calendar |
| -E | Egyptian calendar |
| -G | Greek (Athenian) calendar |
| -M | Macedonian calendar |
| -R | Roman (pre-Julian) calendar |
| [none] | Standard Julian calendar |