Two sheriffs are elected annually for the City of London by the Liverymen of the City livery companies. Today's sheriffs have only nominal duties, but the historical officeholders had important judicial responsibilities. They have attended the justices at the Central Criminal Court, Old Bailey, since its original role as the court for the City and Middlesex. The sheriffs live in the Old Bailey during their year of service, so that one of them can always be attendant on the judges. In Court No 1 the principal chairs on the bench are reserved for their and the Lord Mayor's use, with the Sword of the City hanging behind the bench. It is an invariable custom that the Lord Mayor of London must previously have served as a sheriff. By a "custom of immemorial usage in the City", the two sheriffs are elected at the Midsummer Common Hall by the Liverymen by acclamation, unless a ballot is demanded from the floor, which takes place within fourteen days. The returning officers at the Common Hall are the Recorder of London (senior Circuit Judge at the Central Criminal Court) and the outgoing Sheriffs. As elected officers from the 7th century (excepting 1067 to 1132), the sheriffs' jurisdiction covers the square mile of the City of London, and from the middle ages to the 1890s Middlesex also. The 1960s creation of High Sheriff of Greater London now covers areas of London outside the City. Source: Wikipedia (en)