The earliest recorded Mayor of London was in 1189. Today, the Lord Mayor, based at Mansion House, works for Britain as a whole and promotes the City of London’s business and financial capabilities. In addition to presiding over the Courts of Aldermen and Common Council, he has a significant number of other official roles.
The Lord Mayor serves for a year and is elected at the end of September in the Great Hall of Guildhall. He or she is elected by an assembly, known as Common Hall, including all Liverymen of at least one year's standing. The Lord Mayor is assisted in his or her duties by two Sheriffs who are elected on Midsummer Day each year in Common Hall.
The new Lord Mayor takes office in November, the day before the Lord Mayor's Show. The Livery Companies are traditionally represented in the procession and when it reaches the Mansion House, members wearing their livery robes greet the Lord Mayor.
One of the two Sheriffs comes from the Court of Aldermen (the Aldermanic Sheriff), and the other has to be a Liveryman of a City Company (the Lay Sheriff). They take office on Michaelmas Eve in late September for a year.