People have names for identification purposes and for referencing lineage. In early or primitive societies, people used only one name for identification because populations were small. As populations grew in different areas, inhabitants used a second name or a surname to further identify themselves.
One method to identify someone was to use a descriptive word that referred to the individual or his occupation. For example, "Harold the blacksmith" and "Erik the Red" are names that describe the person's occupation or refer to hair color.
Similarly, the history of surnames or family names refer to an individual's father's name. Usually, a son would be referred to as "his given name" followed by "son of father's name," such as "Leif, son of Eric," or "Leif Erickson." This practice of taking the father's name to form a son's name is called patronymic naming, which also is a way of conveying lineage.