The purpose of applying dendrochronology to art historical problems is to establish, in the case of panel paintings, a felling date for the tree(s) from which the wood panel was made. Most 15th-century panel paintings tend to be neither signed nor dated: tree-ring analysis of the panels attributed to Rogier van der Weyden and to Robert Campion resulted in new criteria regarding their attribution. In addition to felling date, it is also possible to determine length of storage period before wood was used and provenance of the source tree. A few paintings and five altarpieces of Rogier van der Weyden and five paintings of Campion were examined for this study. See also <i>AATA</i> <b>24-45</b>, <b>24-625</b>, <b>25-30</b>, <b>25-493</b>, and <b>26-1489</b>.