I am trying to get a handle on what kind of marriages would have been prohibited legally and church-wise in JA's time. I am thinking in regards to Darcy and Anne de Bourgh. I believe that there were some prohibitions regarding consanguinity at one time in English history, but I am not sure if the Anglican church carried through with that, and how far it was carried through.

Emma and Mr. Knightly are a little different, as there does not seem to be any blood connection, but I was wondering if it would be likely if they would have had to receive any special dispensation.

Any info out there on what the exact prohibitions would be?