The Chronicle of Nantes records a donation by "Herispogii" for the soul of "Marmohec coniugis nostrĉ" dated 857, which suggests that she was then deceased... 1
Marriage Information:
Marmohec married Erispoë, duc de Bretagne, son of Nominoë, duc de Bretagne. (Erispoë, duc de Bretagne died on 12 Nov 857.)