SoG Leaflet: The relevance of surnames

All our original ancestors used a one-part name, whether they were Celts, Anglo-Saxons, Scandinavians or Normans.
Certain people before the Norman conquest, and in growing numbers afterwards, had an additional 'byname', but these were not hereditary surnames in the modern sense as they did not pass from father to son.

Such names may appear in Domesday Book, but they have no relevance here. It was not until the early 12th century that surnames became hereditary among the nobility. They spread gradually amongst the ordinary people in the next century, from the town to the country and from the south of England to the north. Most people in England did not, however, have anything approaching an hereditary surname until the end of the 14th century.

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The growing need for identification in mediaeval England had probably led the clerks to give people these additional names.
They might be those of their fathers (patronymics) or of some other relation, or the name of the place where they lived or from which they had come (locative surnames), or the names of their offices or occupations, or some descriptive or nick-name.

These additional names might vary considerably during a man's life, change from generation to generation, be changed at apprenticeship or be subject to translation by the clerks at their whim, so that the process by which they became fixed and passed from father to son was quite accidental.

These people themselves sometimes used different names from those by which they were known by the clerks. Thus no clue can be obtained from the surname alone as to the original nationality or racial origin of a family.