Marrying Your Cousin?

I ran across something interesting in some marriage records I was working with recently. There were some pages inserted among the usual forms. What were they? While written in Latin, I deduced that these were dispensations from consanguinity allowing the marriage to take place. Consanguinity? It's a fancy term for marrying someone who is blood related (usually a cousin).

There have always been rules against marrying blood relatives (incest) but those rules varied with time and place. Generally marriage was not allowed among persons related closer than the fourth degree. This means that relationships closer than third cousins would require a dispensation if the marriage was to occur. The lower the degree, the harder it would be to obtain a dispensation. Degree is counted from the prospective bride or groom to the nearest common ancestor. The higher number is used if the degrees are different. For example, if the common ancestor was a grandparent, the degree would be 2 and the marriage would be forbidden (They are first cousins.)

I know my first cousins and most of my second cousins. I know a few of my third cousins but only because of my genealogy work. That is to say, I run the risk of a consanguinous marriage without further research. In a diverse land like the United States, we probably simply assume that a prospective mate is not blood related. But what about marriages in some of our smaller ancestral villages where people were less mobile? Did someone track the genealogy or was there an assumption that if no one remembered a relationship, then it was too far removed to worry about? I suspect it was the latter.

PS: I saw a couple of degree 1 dispensations in my work recently. Did that mean a brother and sister wanted get married? It turns out that these are people who wanted to marry their brother-in-law or sister-in-law after the death of their spouse. The term 'affinity' is used in these cases instead of 'consanguinity' because they are not blood related.