history

Pearly Kings & Queens originated in the 19th century from the 'Coster Kings & Queens', who originated in the 18th century, who originated from the 'Costermongers', who originated from London's 'Street Traders', who have been around for over a 1000 years... with that out of the way let's get down to the nitty gritty!
Street traders, or 'Costermongers' as they became known, have been an important feature of London life since the 11th century - and for the best part of 900 of those years they were unlicensed and itinerant - at times hounded by the authorities & bureaucracy. They cried their wares to attract customers with vigour and panache - much to the annoyance of London's 'well-to-do' society - yet they provided an essential service to London's poor; mainly selling their wares in small quantities around the streets & alleyways - at first from baskets, then progressing to barrows - then permanent static pitches from stalls - until they finally evolved into today's familiar and popular Markets. Oh yes, we owe a great deal to our ancestral costermongers - but like so many things we take for granted today, their fight was long and hard.
Because of London's unique geographical position it grew and thrived as a trading centre - the City grew up not just around its financial market, but around its famous markets that provided the necessities of life - markets such as Billingsgate (where the fish were landed), Smithfield (for cattle & livestock) and Covent Garden and Spitalfields (for fruit, veg & flowers).
Although each Coster family traded independently, they remained loyal to other costers - collecting for those that fell on particularly hard times. Their philosophy of life was one of fate - some you win, some you lose - when things went bad you just had to pick yourself up and start all over again.
They liked a gamble - be it on boxing matches, pigeon racing, dog fighting and even rat-killing matches! Most of all, of course, they liked to indulge in a tipple or two. Not because they enjoyed a good old booze-up and sing-song, you understand - 'no guv', more to do with being suspicious of water, what with cholera & typhoid and all that! Besides, the Ale Houses, Gin Palaces & the Penny Gaff Music Halls were warm & welcoming compared to their squalid lodgings. By now most of London's poorer working classes were hoarded together outside the thriving City - dockers, sailors, immigrants & factory girls - all living in slum conditions with little or no sanitation.
They liked a gamble - be it on boxing matches, pigeon racing, dog fighting and even rat-killing matches! Most of all, of course, they liked to indulge in a tipple or two. Not because they enjoyed a good old booze-up and sing-song, you understand - 'no guv', more to do with being suspicious of water, what with cholera & typhoid and all that! Besides, the Ale Houses, Gin Palaces & the Penny Gaff Music Halls were warm & welcoming compared to their squalid lodgings. By now most of London's poorer working classes were hoarded together outside the thriving City - dockers, sailors, immigrants & factory girls - all living in slum conditions with little or no sanitation.
born within the sounds of bow bells

St Mary le Bow with its bell tower - photograph dates from 1909
The traditional definition of Cockneys is that they should be born within the sound of Bow bells. There is one big problem with that: when the Second World War broke out, church bells no longer rang except as a warning.
Another problem is that the bell tower of St Mary le Bow in Cheapside, London, that housed Bow bells, was hit by a German bomb in 1941. It wasn't rebuilt until 1961. Does this mean no Cockneys were born in those 20 years because nobody could hear Bow bells?
In fact, nowadays, there is very little residential property around St Mary le Bow and it's unlikely there are many babies born within earshot of it.
The church itself says it is "...serving all who work in and visit the City of London. The church opens at 7.00am each weekday..." rather suggesting it has few local residential parishioners.
There still seems to be plenty of Cockneys in London and they aren't all over 67 years old either, so there must be some other definition.