According to
legend:
St Michael the Archangel appeared in a dream
to St Aubert, the Bishop of Avranches
and commanded him to built a monastery on this site.
The Bishop resisted this direction as just a dream
until waking up with a bruise after the 3rd dream.
The monastery was founded about the year 708
The ambitious constuction seen today
was begun in 1017
and completed in 1520