Here is another plugin that lets you add simple vertical timelines to your website without a whole lot of effort and coding. Simple Vertical Timeline for WordPress allows you to add timelines to your posts via a simple shortcode to display events and everything in between.
You get two buttons to create a timeline and add events to it. For each event, you can change title, notes, date, and node color. The script takes care of the rest.
This is a free plugin. You can download it here.