Start_date error when adding blog posts

Trying to set up a historical timeline as well. I’ve found a few problems I need your help on.

1. When adding blog posts as timeline events I get the error Missing start_date [_1571_ad_] I am not seeing a place to add a start date/year outside of modern times.

2. There is no way to override the JS date formats and calendar functionality for older dates than the calendar function can go.

3. Would you consider allowing a start_date for the timeline as an added attribute to the short code?

https://wordpress.org/plugins/timelinejs/