Heiresses are women, usually daughters of men with no male heirs, who come into property in their own right.
The liege lord generally takes control of all the property of an heiress, taking its income for himself for the duration of her spinsterhood, merely providing for her welfare out of her coffers. Since the income is usually much more than the expense of keeping a rich maiden, lords like to have heiresses in their care, and are often in no hurry to have them wed.
Because the hand of a rich heiress is the greatest prize that can be awarded to a loyal retainer for his service, many knights maintain their bachelorhood in the hopes of receiving just such a reward.
The law of the land requires that, if an heiress is widowed, her liege lord may have her take a second husband of the lord’s choosing. However, law also holds that a woman cannot be forced to marry a third time. If she finds love after being widowed a second time, she must obtain her lord’s permission to marry, as before, but she has no obligation to marry. Further, she can now, unencumbered, exercise all other rights of possession. Knights may swear fealty to her, she determines how to spend the fief’s money, and so on. Such an heiress is quite independent and powerful.