] 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.

Interestingly, Emma's children and Isabella's children would have been what is known as double-first cousins as their fathers were brothers (as well as their mothers being sisters). First cousins are, I believe, the closest example of consanguinity allowed by the church to marry.

I wonder what the church would have said if any of Mr. & Mrs. John Knightly's five children wished to marry one of Emma and Mr. Knightley's children (assuming they had some.)? Were double-first cousins regarded as a closer form of consanguinity?