Why do people have family names?
The short answer
Family names help distinguish people and preserve information about family, place, occupation, or another connection. Their meanings and social roles have changed across places and time.
Why a given name was not enough
In a small community, one name might be sufficient. As communities grew, the same given names were repeated. Adding information such as a parent, place, or occupation made identification easier.
What a surname can and cannot tell us
Some surnames came from places or occupations, but a modern surname does not always preserve its original meaning exactly. Genealogical research should compare names with records of dates, places, and relationships.