If you need to sort BC dates or dates < 1000 AD, using the built in Liquid sorting doesn't work. This example implements a JS based version of the Timeline instead.
- From your metadata's "date" field create a new column "year" that is only the year, all values must be a number. For BC dates, the year should be a negative number.
- In your template replace "_layouts/timeline.html" and "_includes/js/timeline-js.html" with the version in this gist.
If you want to use TimelineJS feature, you will also want to edit the "assets/data/timelinejs.json" to use item.year
rather than parsing the date.