In 1847, two characters who were destined to change the face of literature--Jane Eyre from Charlotte Bronte's novel of the same name and Becky Sharpe from Vanity Fair were published. Both characters put the profession of governessing at the heart of the English novel for the first time, essentially starting a genre that continues to today. As Kathryn Hughes points out in the Victorian Governess, governesses do appear in novels pre-1847 but generally not at the heart of the novel. She also becomes a familiar figure in Victorian painting (ie The Governess by Richard Redgrave in 1844).
So why the 1840s? What was different? Why was the governess not a popular figure in Regency novels or painting?
First of all, it has to do with the increasing levels of literacy amongst middle class women. Once a market has been established, publishers are quick to follow the trend. They are less quick to be trend setters. So there had to be a market for women's fiction first.
Because there are more servants, middle class women are also able to indulge in reading and reading about governesses proves to be popular.
The governess who moves from orphan to married lady in the course of the novel is following the one path that middle class women of that era were all to pursue without losing their gentility. Unlike men, they could not start their own businesses or go to work in a factory to make their fortune. The governess is an aspirational fantasy for these women. She is an alter ego and is able in theory to wander the world at will, in a way her real life counter part never could.
Starting in about 1830, the middle classes begin to employ governesses. Before this time period, middle class women were either taught by their mothers or went to academies. As the fashion for employing servants increases, the need for women to learn basic skills such as cooking and sewing decreases. The emphasis begins to fall on accomplishments. Lower middle class women whose husbands had made their fortunes in manufacturing did not always possess the requisite skill to pass on to their daughters so they began to employ women who could.
In the 1820s, the craze for ornamental, rather than practical education infects all levels of society. Some in the aspiring middle class did not like to think that others from the lower orders might be mingling with their daughters and thus, they began to employ governesses, rather than sending them to academies. It is slightly ironic that as boys are being out to private boarding schools, girls are being withdrawn from them and taught at home. Aristocrats, of course, had traditionally employed governesses and thus employing a governess was a way of showing that the family had reached the upper echelons. So more positions for governesses opened up and it became a way for women to earn money.
Also in the 1820s and 1830s, many middle class families suffered ruin when banks failed or fathers died without providing properly for their daughters. Thus, there was a larger pool of educated women who were forced to go out and earn a living. These women also wanted the aspirational fantasy and enjoyed reading about their own.
Thus the governess novel came into its own and continues today. In fact, my editor often says how popular the governess as a heroine is. It is the whole Cinderella/rags to riches that is a timeless premise.