-- Improve the timeline marks for readability (use one row with a rounded scale - ...700, 800, 900, 1000, 1100... - and another row for the shown events - ...711, 960, 1112...; ditch the comma and the "CE/BCE". Or, create visualization options).

-- Also improve text readability - event titles should not overlap.

-- Avoid page layout jerks when clicking on items (depending e.g. on amount of rows in the "event description" box.

-- Add granularity of details ("most important events" vs "important events" vs "interesting events"...).

-- Add a mode in which all the "description" texts are listed in a table (instead of being constrained in a box, one at a time).

...

Very good job.