As I explained in my last post, marriage was encouraged by German nobility, as long as it was within the familiae. If the marriage was outside the lord’s retinue, the children of that marriage belonged to the mother’s lord. Therefore, the father’s lord would be gaining nothing by the union.
In some cases, two lords would negotiate a marriage, and divide the children between them. This was particularly true if the knight’s fiefs were allods passed down to his children. Often, daughters were given allods from either their fathers or their mothers, and could be very valuable. Therefore, marriage arrangements became a swapping of people and property, each lord bargaining for the better deal.

Knights could also marry outside the knightly class, by wedding a free woman. In this case, the resulting children were also free. Free persons residing in a lord’s demesne did not have to provide a corvee (service of labor for a specified time), but did have to pay a head tax, similar to our income tax. So, few lords were inclined to approve such a marriage, unless the free woman agreed to relinquish her children’s freedom to the knight’s lord. Another enticement to the lord is that the free woman and her family would pay an agreed sum for the loss of the children.
It was not unusual for free persons to seek marriage into a familiae, to be relieved of the head tax, and to learn the ways of the fighting knightly class. Children of such a union almost always received a fief from the lord, particularly male children who were training to be warriors.
Often, mixed marriages between familiae or free and unfree resulted in later arguments, litigation, and outright kidnappings or violent skirmishes. Only the highest bishopric or ducal courts could make decisions in such cases, and seldom were bothered to do so. The might of the warrior class almost always won with or without the courts.