James Davidson in the London Review of Books:
In the early 1800s, nearly 25 per cent of all females in the United Kingdom were called Mary. If you add to these many Marys the crushing numbers of Elizabeths, Sarahs, Janes and variform Anns (Nancys, Nans and Hannahs), you would have the Christian names of something close to 80 per cent of the female population. There was a similar pattern with Johns. About one fifth of all males in the UK between 1800 and 1850 were christened John and the vast majority of the other men and boys around at the time were Joseph, James, Thomas or William.
Around 1850, however, the repertoire of names in regular use began to increase rapidly. As Gothic-looking steeples rose around the country, so medieval-sounding names crowded around the font: Arthur, Walter, Harold and Neville, Ethel, Edith and Dorothy, soon to be supplemented by endless Geoffreys. This remarkable efflorescence has been described as a ‘personalisation’ of names, although since in this period the ‘proper’ name one gave to registrars and census enumerators might very well be supplemented by a highly personalised nickname – Old Tom, Long Tom, Short Tom, or even, according to Rev. Alfred Easther, a 19th-century Yorkshire dialectologist, Wantem, Blackcop and Muddlinpin – it might better be described as an outbreak of name-consumerism, as parents increasingly invested their energies in baptismal choice.
Children were no longer necessarily named after parents, grandparents, aunts and uncles. Indeed, parents began to choose names and forms of names simply because they liked them or because they reminded them of someone they liked, in life, in fiction or in a Shakespeare comedy: Olivia, for example.
More here.