David Edelman <pappapeach@gmail.com> wrote:

There has been discussions about cousin and sibling marriage. This is
a different questain, but with a family kind of marriage:
If you go back in history of, say, 100-150 years, we get the
impression that a lot of comunities were much smaller then they are
now. It is known that travel then was much slower, dangerous, and more
expensive then it is now.
Because of that combination, it has been mentioned that a young man
will travel about 50 miles, to the next village, to "find" his wife.
This is the questain:
Lets say, about two years after this first young mans goes to the
neighbore village where he "found" his wife, his younger brother goes
to the same village to also "get" a wife. This second wife happens to
be the sister of the first wife. This would then make the two
brothers, brother-in-laws: the two sisters, sister-in-laws.
Similarly, although slightly different, if the younger brother is not
the brother of the first husband, but the younger brother of the first
wife, and goes to the first village. You end up with the same result
in the end.
It would seem this should have been common, but I have never seen it.
I have only seen it once, in present San Francisco, where two sisters
are married to two brothers.
Was this common, not aloud, or what?

Very common, I think.

It's a custom in some circles, in particular among Lubavitch
Chassidim, that in these cases the two couples should live in
different cities. See e.g.
<http://www.sichosinenglish.org/books/eternal-joy-1/15.htm>

BTW, my grandmother's two sisters married two brothers. Apparently
a third brother was interested in my grandmother, but she had other
ideas.

Robert Israel
israel@math.ubc.ca
Vancouver, BC, Canada