[Avodah] cherem of Rabbenu Gershom

[Eli Turkel]

<<Question: What was the driving force behind the takkana of rabbeinu
gershom on monogamy?>>

According to historians it was because the surrounding Xtian society
was monogamous as distinct from the Moslem community. I doubt you
would find any posek saying this but rather stressing family stability
(what not the sefardim?)
I have seen articles claiming that ashkenazi rishonim were more
pro-women in general than sefardi rishonim because of the mores of the
surrounding societies.

Just read an article about the yeshivot of Baalei haTosafot and
remarking that they appeared at the same time as the beginnings of the
university in Europe. The author stresses that it does not mean that
one group copied from the other but rather the ideas were in the air
and developed independently. The same notion can apply to other areas.

As an aside historians discuss whether Rabbenu Gershom ever issued an
edict against bigamy. The  references are many years later and the
recodrs of the time indicate numerous takkanot of Rabbenu Gershom
(actually his bet din) but not including bigamy or opening of letters
-- 
Eli Turkel