The form is determined by the father's name. In the more common form, the final vowel of the name is replaced with -ez . Most scholars consider that this is derived from the Latin genitive form. A smaller group of names are used as patronymic bynames without being modified in any way. The following table includes names and their patronymic forms.
Patronymic bynames seem to have played several roles.
Some seem to be hereditary surnames referring to the residence or history of the family. Others seem to be individual bynames, describing where the person was born or lives. In Portuguese, de comes in a variety of forms. It is often elided with the word following it. Feminine placenames are more likely to be marked than masculine placenames.