I am copying from the Austrian Genteam List the
article translated by Mr. Helmut Mueller:
In 1726, due the order of the Habsburg ruler Charles VI, the number of
Jewish families was limited by quota to 8,541 in Bohemia and 5,106 in
To enforce this quota (or "numerus clausus"), a so-called
order was issued. According to this order, only the first-born son
of each Jewish family was given permission to marry (called a "copulatio
consensus"). The permits could also be sold if there were no son
to inherit them. The Familianten order was in force until 1848.
As a result, many Jews who could not obtain marriage permits emigrated
from Bohemia and Moravia. For example, by 1900 almost half of the
Jews in Hungary were of Bohemian or Moravian descent.
Submitted by MFG Helmut (Müller) to the Austrian Genteam