Title: {{oldest:%B %d, %Y}}
Created: 2026-06-13T15:55:09-04:00
Modified: 2026-06-13T15:55:09-04:00

<p>
    The <b>&lbrace;&lbrace;oldest:%B %d, %Y&rbrace;&rbrace;</b> substitution
    parameter references the oldest created or modified time of a node, or any
    of its child nodes, and formats the date/time value using an
    <a href="https://www.man7.org/linux/man-pages/man3/strftime.3.html">strftime</a>
    format string in the rvalue portion of the parameter.
</p>

<p>
    In other words, the
    <b>&lbrace;&lbrace;oldest:%B %d, %Y&rbrace;&rbrace;</b> parameter lets you
    display the oldest date that is found in a given node, or any node found
    underneath it in the tree.
</p>

<p>
    This can be especially useful for setting copyright dates, or displaying
    the date that anything in a section of your web site was last updated.
</p>

<p>
    For example, this node has the following {{node-link:headers/created}} and
    {{node-link:headers/modified}} headers set:
</p>

<pre>Created: {{value:created}}
Modified: {{value:modified}}</pre>

<p>
    However, this node also has a
    <a href="{{node-url:parameters/oldest/future}}">child node</a>, with the
    following headers set in the distant past:
</p>

<pre>Created: 1970-01-01T00:00:00-00:00
Modified: 1970-01-11T00:00:00-00:00</pre>

<p>
    Because the dates on the child node are in the past (relatively
    speaking), here is what the
    <b>&lbrace;&lbrace;oldest:%B %d, %Y&rbrace;&rbrace;</b>
    substitution parameter evaluates to on this node:
</p>

<pre>{{oldest:%B %d, %Y}}</pre>

<p>
    The <b>&lbrace;&lbrace;oldest:%B %d, %Y&rbrace;&rbrace;</b> parameter
    checks all of the dates for every node in the tree, starting from the
    current node and working its way down, and evaluates to the oldest date
    that it finds in any of the nodes.
</p>

<p>
    On this node, this evaluates to:
</p>

<pre>&copy; {{oldest:%Y}} Foo Bar, Inc.</pre>

<p>
    The format string has a lot of different options. See the
    <a href="https://docs.python.org/3.14/library/datetime.html#strftime-and-strptime-format-codes">Python datetime strftime() reference</a>
    or the
    <a href="https://www.man7.org/linux/man-pages/man3/strftime.3.html">strftime(3)</a>
    man page for further details.
</p>

<p>
    Compare this with the {{node-link:parameters/created}},
    {{node-link:parameters/modified}}, and
    {{node-link:parameters/latest/index}} parameters.
</p>

