Building a hierarchical representation of an ATOM feed based on dates is challenging with XSLT. Using "Muenchian Method" it's quite easy. http://www.jenitennison.com/xslt/grouping/muenchian.html The following xslt script takes an ATOM feed and creates a hierarchical xml grouping posts by years, months and day. 1: <?xml version="1.0" encoding="utf-8"?>
2: <!--http://www.jenitennison.com/xslt/grouping/muenchian.html -->
3: <xsl:stylesheet version="1.0"
4: xmlns:atom="http://www.w3.org/2005/Atom"
5: xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
6: xmlns:dc="http://purl.org/dc/elements/1.1/">
7: <xsl:output method="xml"/>
8: <xsl:template match="/">
9: ...