TimeStory has an absolute maximum date range of 1,000,000 BC through 100,000 AD. Most timelines, of course, only need a tiny sliver of that range, often just for current, near-past, and near-future dates, but TimeStory does support building timelines of ancient history and prehistory.

Before 4713 BC, only year numbers are supported; there’s no way to select a specific day or month. (In practice, of course, we don’t have exact calendar days for most ancient dates even within that day-granularity range; this range is just a technical limit.)

You can type arbitrary dates or years into any input field using your local date conventions, such as “1/1/2025” or “50,000 BCE”. TimeStory tries to be lenient, allowing entry of dates in a variety of formats; for example, if your language uses BC and AD, TimeStory will also accept BCE and CE.

In many date entry fields, you can also click on the calendar button to bring up the macOS standard date picker. Be aware, though, that it does not support the entire date range that TimeStory does; for far BC or AD dates, you may need to type them in.

## Historical calendar details

Dates from October 4, 1582 down to TimeStory’s lower limits use the proleptic Julian calendar, and dates starting on October 15, 1582 use the Gregorian calendar. (Due to the deliberate correction applied with the new calendar, the Gregorian date October 15, 1582 immediately followed the Julian date October 4, 1582.)

## Prior TimeStory version limits

Versions of TimeStory up through 3.7 had an absolute lower date limit of 4,713 BC, due to some internal date representation limitations. Version 3.8 moved that limit back to 500,000 BC, and version 3.10 moved it to the current limit of 1,000,000 BC.