Under the Anglo-Saxon kings, London was governed by a royal official called a ‘portreeve’ (town-agent). Local administration was by an assembly of leading citizens, the ‘aldermen’ (chief men).
After 1066 French immigrants from cities such as Rouen introduced the idea that a city could govern itself and choose its own chief magistrate, the mayor. London got its first mayor in about 1189.
As the City grew and administration became more complex, full-time officials such as a town clerk and a chamberlain (treasurer) were appointed, and in the 1300s another wider assembly, the Common Council, came into existence. Only men who were ‘citizens’ had any say in the City’s affairs.