The older London companies began as craft/trade guilds, many of which became livery companies, by royal charter, from the late 14th century on (and especially from the late 15th century). Others began later, independently or as mergings of older groups, and continue to be established today. Originally the companies were important regulatory, political, social, and religious bodies within the city's governmental structure. Today, although still of considerable importance, they are private associations, most with websites which provide information on their history and on their current activities. Links to these websites appear on the right for companies existing today to which mayors and sheriffs belong and/or have belonged; urls are checked once a year. Names listed without links are of companies without websites, defunct companies, or (from the very early years) occupations rather than companies.
Every London mayor and sheriff from at least 1319, and probably from well before then also, has belonged to at least one London company (originally, guild). In 1319, for example, acquisition of the freedom of London--the right at that time to do business within the city and to participate in its governance--was stated by royal charter to be possible only through a company (see A.B. Beaven, The Aldermen of the City of London (1908--13), I.329). In the earliest years for which written records of London’s mayors and sheriffs exist, records may be of an individual’s trade or occupation rather than of his guild membership (the two did not always coincide; and various guilds also began at different times, with their origins sometimes unclear). There is often no way, however, of determining from the records which is being noted, and this database simply provides whatever information has been found.
Except for one brief period in the early 15th century, until some time in the 18th century it was apparently usual (see Beaven I.333, and his chronological listings of aldermen passim) for a mayor or a sheriff to belong to only one company. If an individual wished to belong to a company other than the one he originally joined, he (until 1981 a sheriff or mayor was always a he) had to be officially transferred to the new company, through a process known as translation, to which both the individual's original company and his intended new company had to agree. In translation (which involved the Court of Aldermen), the individual's official city company registration (from when his freedom was acquired) was changed; he became recorded as a member of the new company, and was no longer a member of the original one. Translation was not uncommon before 1800, as from at least the late 13th century until the mid 16th century an alderman, and until 1742 a mayor, had to belong to one of the so-called Great Twelve companies: the companies then of the greatest influence and wealth in the city. (See Beaven I.329--31.) These were (and still are), in order of ceremonial precedence, the Mercers, Grocers, Drapers, Fishmongers, Goldsmiths, Merchant Taylors, Skinners, Haberdashers, Salters, Ironmongers, Vintners, and Clothworkers. (In the 16th century it was arranged that the Merchant Taylors and Skinners would alternate in sixth place year by year.) An individual in a non-Great company who was well placed to become an alderman, sheriff, and perhaps eventually mayor would translate to a Great Twelve company sometimes early on in his career, sometimes shortly before an election in which he planned to run, and sometimes immediately after election (before being sworn). One could become a sheriff without being an alderman, but a mayor had to be an alderman, from early on; and from December 1385 (Beaven II.xxv) a mayor had to have served previously as a sheriff. In the mid 16th century, however, the Great Twelve custom was abandoned for aldermen, and in 1742 it was ruled that a mayor did not have to belong to a Great Twelve company (Beaven I.330--33). Translation gradually became uncommon; and by the late 18th century (although the first case found so far is in the 1720s) mayors and sheriffs begin to be recorded as belonging to more than one company. By the mid to late 19th century, many belonged to two or more companies.
When a sheriff or mayor joined one or more other companies subsequent to the original one, the original company of freedom registration became known as the parent (Beaven's term) or mother (today's term) company. This database, like Beaven, provides for each sheriff and mayor, in his/her main listing, his/her only company or original/parent/mother company (or company of translation, if any), with additional companies in the footnotes. In a few cases, records disagree as to an individual's parent/mother company; such cases are discussed in the footnotes. Possible causes of such disagreements include, besides simple errors, overlooked translations and intentional or unintentional exceptions. Research in this area is ongoing.