@mujie wrote:
What makes you say all millers have the surname Mills?
Because last names actually came about via ones occupation ie. “Smith” (blacksmith), “Eisenhauer” (iron worker, later Anglicized in America as “Eisenhower”) or “Schneider” (tailor) as well as more complicated names based on occupational titles.
In England it was common for servants to take a modified version of their employer’s occupation or first name as their last name, adding the letter “s” to the word, although this formation could also be a patronymic. For instance, the surname “Vickers” is thought to have arisen as an occupational name adopted by the servant of a vicar, while “Roberts” could have been adopted by either the son or the servant of a man named Robert.
A subset of occupational names in English are names thought to be derived from the medieval mystery plays. The participants would often play the same roles for life, passing the part down to their oldest sons. Names derived from this may include “King”, “Lord”, “Virgin”, and “Death”; the last is often wrongly thought to be an Anglicization of the French name “D’Ath”.
The other way last names came about was location- ie “Gorski” (Polish for “hill”) or “Pitt” (variant of “pit”), but may also refer to specific locations. “Washington”, for instance, is thought to mean “the homestead of the family of Wassa”, while “Lucci” likely means “resident of Lucca”.
Although some surnames (such as “London” or “Bialystok”) are derived from large cities, more people reflect the names of smaller communities, as in Ó Creachmhaoil, derived from a village in County Galway.
This is thought to be due to the tendency in Europe during the Middle Ages for migration to chiefly be from smaller communities to the cities, and the need for new arrivals to choose a defining surname.