But in general, it is important to understand that a Page in Hugo can be either a list page or a leaf page (leaf = no children).

So when you do a `{{ range first 5 .Data.Pages.ByDate }}` you get a list of the pages that is a child of that page. For the home page, this is all the pages, for a section, it is the pages in that section etc. For a regular content page, there aren't any pages to show (no children).

Depending on what you want to show, this may be an option:

```
<div id="sidebar">
{{ if .IsPage }}
    {{ range first 5 .Site.Pages.ByDate }}
        <h1><a href="{{ .Permalink }}">{{ .Title }}</a></h1>
    {{ end }}
{{ else }}
    {{ range first 5 .Data.Pages.ByDate }}
        <h1><a href="{{ .Permalink }}">{{ .Title }}</a></h1>
    {{ end }}
{{ end }}
</div>
```