Double Em Ref

Emblem Glyphs in Classic Maya Inscriptions: From Single to Double Ones as a
Means of Place of Origin, Memory and Diaspora, in Daniel Graña-Behrens
(ed.) Places of Power and Memory in Mesoamerica's Past and Present: How
Sites, Toponyms and Landscapes Shape History and Remembrance, ESTUDIOS
INDIANA 9, Ibero-Amerikasches Institut, Preußischer Kulturbesitz. Mann
Verlag, Berlin, pp. 123-158.

The use of more than one emblem glyph as royal title is one of the least
explained features of Classic Maya politics. Epigraphers suggest that
double or triple emblem glyphs indicate dynastic mergers, although in
several cases it could point to the move of a dynasty from one place to
another. Women played an important part in connecting royal houses but in
many instances their role is not well spelled out in the inscriptions.
There is no overall pattern, however examination of several examples from
different regions allows to propose plausible explanations on why certain
rulers had double emblem glyphs.

http://www.iai.spk-
berlin.de/fileadmin/dokumentenbibliothek/Estudios_Indiana/IE9_online.pdf