He is called as Mayor because here in India the administrative heads and their elections process is mostly a legacy which Britishers left over here as it was after the beginning of the 12th century, the title of portreeve(chief magistrate of London bore the title of portreeve gave way to that of mayor as the designation of the chief officer of London.Later on the adoption of the title by other boroughs followed at various intervals. In the 19th century, in the United Kingdom, the Municipal Corporations Act 1882, Section 15, regulated the election of mayors.